1
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Ibabe Á, Steffensen GO, Casal I, Gómez M, Kanne T, Nygård J, Levy Yeyati A, Lee EJH. Heat Dissipation Mechanisms in Hybrid Superconductor-Semiconductor Devices Revealed by Joule Spectroscopy. NANO LETTERS 2024; 24:6488-6495. [PMID: 38771151 PMCID: PMC11157656 DOI: 10.1021/acs.nanolett.4c00574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/17/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Understanding heating and cooling mechanisms in mesoscopic superconductor-semiconductor devices is crucial for their application in quantum technologies. Owing to their poor thermal conductivity, heating effects can drive superconducting-to-normal transitions even at low bias, observed as sharp conductance dips through the loss of Andreev excess currents. Tracking such dips across magnetic field, cryostat temperature, and applied microwave power allows us to uncover cooling bottlenecks in different parts of a device. By applying this "Joule spectroscopy" technique, we analyze heat dissipation in devices based on InAs-Al nanowires and reveal that cooling of superconducting islands is limited by the rather inefficient electron-phonon coupling, as opposed to grounded superconductors that primarily cool by quasiparticle diffusion. We show that powers as low as 50-150 pW are able to suppress superconductivity on the islands. Applied microwaves lead to similar heating effects but are affected by the interplay of the microwave frequency and the effective electron-phonon relaxation time.
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Affiliation(s)
- Ángel Ibabe
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
| | - Gorm O. Steffensen
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Ignacio Casal
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
| | - Mario Gómez
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
| | - Thomas Kanne
- Center
for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Jesper Nygård
- Center
for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Alfredo Levy Yeyati
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Nicolás Cabrera, Universidad Autónoma
de Madrid, E-28049 Madrid, Spain
| | - Eduardo J. H. Lee
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Nicolás Cabrera, Universidad Autónoma
de Madrid, E-28049 Madrid, Spain
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2
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Connolly T, Kurilovich PD, Diamond S, Nho H, Bøttcher CGL, Glazman LI, Fatemi V, Devoret MH. Coexistence of Nonequilibrium Density and Equilibrium Energy Distribution of Quasiparticles in a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2024; 132:217001. [PMID: 38856268 DOI: 10.1103/physrevlett.132.217001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 08/10/2023] [Accepted: 03/21/2024] [Indexed: 06/11/2024]
Abstract
The density of quasiparticles typically observed in superconducting qubits exceeds the value expected in equilibrium by many orders of magnitude. Can this out-of-equilibrium quasiparticle density still possess an energy distribution in equilibrium with the phonon bath? Here, we answer this question affirmatively by measuring the thermal activation of charge-parity switching in a transmon qubit with a difference in superconducting gap on the two sides of the Josephson junction. We then demonstrate how the gap asymmetry of the device can be exploited to manipulate its parity.
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Affiliation(s)
- Thomas Connolly
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Pavel D Kurilovich
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Spencer Diamond
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Heekun Nho
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Charlotte G L Bøttcher
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Leonid I Glazman
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Valla Fatemi
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Michel H Devoret
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA
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3
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Kono S, Pan J, Chegnizadeh M, Wang X, Youssefi A, Scigliuzzo M, Kippenberg TJ. Mechanically induced correlated errors on superconducting qubits with relaxation times exceeding 0.4 ms. Nat Commun 2024; 15:3950. [PMID: 38729959 PMCID: PMC11087564 DOI: 10.1038/s41467-024-48230-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 04/24/2024] [Indexed: 05/12/2024] Open
Abstract
Superconducting qubits are among the most advanced candidates for achieving fault-tolerant quantum computing. Despite recent significant advancements in the qubit lifetimes, the origin of the loss mechanism for state-of-the-art qubits is still subject to investigation. Furthermore, the successful implementation of quantum error correction requires negligible correlated errors between qubits. Here, we realize long-lived superconducting transmon qubits that exhibit fluctuating lifetimes, averaging 0.2 ms and exceeding 0.4 ms - corresponding to quality factors above 5 million and 10 million, respectively. We then investigate their dominant error mechanism. By introducing novel time-resolved error measurements that are synchronized with the operation of the pulse tube cooler in a dilution refrigerator, we find that mechanical vibrations from the pulse tube induce nonequilibrium dynamics in highly coherent qubits, leading to their correlated bit-flip errors. Our findings not only deepen our understanding of the qubit error mechanisms but also provide valuable insights into potential error-mitigation strategies for achieving fault tolerance by decoupling superconducting qubits from their mechanical environments.
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Affiliation(s)
- Shingo Kono
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland.
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland.
| | - Jiahe Pan
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland
| | - Mahdi Chegnizadeh
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland
| | - Xuxin Wang
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland
| | - Amir Youssefi
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland
| | - Marco Scigliuzzo
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland
| | - Tobias J Kippenberg
- Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland.
- Center for Quantum Science and Engineering, EPFL, Lausanne, Switzerland.
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4
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Ganjam S, Wang Y, Lu Y, Banerjee A, Lei CU, Krayzman L, Kisslinger K, Zhou C, Li R, Jia Y, Liu M, Frunzio L, Schoelkopf RJ. Surpassing millisecond coherence in on chip superconducting quantum memories by optimizing materials and circuit design. Nat Commun 2024; 15:3687. [PMID: 38693124 PMCID: PMC11063213 DOI: 10.1038/s41467-024-47857-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
The performance of superconducting quantum circuits for quantum computing has advanced tremendously in recent decades; however, a comprehensive understanding of relaxation mechanisms does not yet exist. In this work, we utilize a multimode approach to characterizing energy losses in superconducting quantum circuits, with the goals of predicting device performance and improving coherence through materials, process, and circuit design optimization. Using this approach, we measure significant reductions in surface and bulk dielectric losses by employing a tantalum-based materials platform and annealed sapphire substrates. With this knowledge we predict the relaxation times of aluminum- and tantalum-based transmon qubits, and find that they are consistent with experimental results. We additionally optimize device geometry to maximize coherence within a coaxial tunnel architecture, and realize on-chip quantum memories with single-photon Ramsey times of 2.0 - 2.7 ms, limited by their energy relaxation times of 1.0 - 1.4 ms. These results demonstrate an advancement towards a more modular and compact coaxial circuit architecture for bosonic qubits with reproducibly high coherence.
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Affiliation(s)
- Suhas Ganjam
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA.
| | - Yanhao Wang
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Yao Lu
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Archan Banerjee
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Chan U Lei
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Lev Krayzman
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Kim Kisslinger
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Chenyu Zhou
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Ruoshui Li
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Yichen Jia
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Mingzhao Liu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, 11973, NY, USA
| | - Luigi Frunzio
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA
| | - Robert J Schoelkopf
- Departments of Applied Physics and Physics, Yale University, New Haven, 06511, CT, USA.
- Yale Quantum Institute, Yale University, New Haven, 06511, CT, USA.
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5
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Shirizly L, Misguich G, Landa H. Dissipative Dynamics of Graph-State Stabilizers with Superconducting Qubits. PHYSICAL REVIEW LETTERS 2024; 132:010601. [PMID: 38242658 DOI: 10.1103/physrevlett.132.010601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/21/2023] [Accepted: 11/29/2023] [Indexed: 01/21/2024]
Abstract
We study experimentally and numerically the noisy evolution of multipartite entangled states, focusing on superconducting qubit devices accessible via the cloud. We find that a valid modeling of the dynamics requires one to properly account for coherent frequency shifts, caused by stochastic charge-parity fluctuations. We introduce an approach modeling the charge-parity splitting using an extended Markovian environment. This approach is numerically scalable to tens of qubits, allowing us to simulate efficiently the dissipative dynamics of some large multiqubit states. Probing the continuous-time dynamics of increasingly larger and more complex initial states with up to 12 coupled qubits in a ring-graph state, we obtain a good agreement of the experiments and simulations. We show that the underlying many-body dynamics generate decays and revivals of stabilizers, which are used extensively in the context of quantum error correction. Furthermore, we demonstrate the mitigation of 2-qubit coherent interactions (crosstalk) using tailored dynamical decoupling sequences. Our noise model and the numerical approach can be valuable to advance the understanding of error correction and mitigation and invite further investigations of their dynamics.
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Affiliation(s)
- Liran Shirizly
- IBM Quantum, IBM Research - Israel, Haifa University Campus, Mount Carmel, Haifa 31905, Israel
| | - Grégoire Misguich
- Université Paris-Saclay, CNRS, CEA, Institut de Physique Théorique, 91191 Gif-sur-Yvette, France
| | - Haggai Landa
- IBM Quantum, IBM Research - Israel, Haifa University Campus, Mount Carmel, Haifa 31905, Israel
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6
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Liu CH, Harrison DC, Patel S, Wilen CD, Rafferty O, Shearrow A, Ballard A, Iaia V, Ku J, Plourde BLT, McDermott R. Quasiparticle Poisoning of Superconducting Qubits from Resonant Absorption of Pair-Breaking Photons. PHYSICAL REVIEW LETTERS 2024; 132:017001. [PMID: 38242669 DOI: 10.1103/physrevlett.132.017001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 11/22/2023] [Accepted: 11/29/2023] [Indexed: 01/21/2024]
Abstract
The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature; these are known as quasiparticles. Observed quasiparticle densities are of order 1 μm^{-3}, tens of orders of magnitude greater than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and can induce dephasing. Here we show that a dominant mechanism for quasiparticle poisoning is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity of the qubit. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticles. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning.
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Affiliation(s)
- C H Liu
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D C Harrison
- Intelligence Community Postdoctoral Research Fellowship Program, Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S Patel
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C D Wilen
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - O Rafferty
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Shearrow
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Ballard
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - V Iaia
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - J Ku
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - B L T Plourde
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - R McDermott
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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7
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Brosco V, Serpico G, Vinokur V, Poccia N, Vool U. Superconducting Qubit Based on Twisted Cuprate Van der Waals Heterostructures. PHYSICAL REVIEW LETTERS 2024; 132:017003. [PMID: 38242651 DOI: 10.1103/physrevlett.132.017003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 01/21/2024]
Abstract
Van-der-Waals assembly enables the fabrication of novel Josephson junctions featuring an atomically sharp interface between two exfoliated and relatively twisted Bi_{2}Sr_{2}CaCu_{2}O_{8+x} (Bi2212) flakes. In a range of twist angles around 45°, the junction provides a regime where the interlayer two-Cooper pair tunneling dominates the current-phase relation. Here we propose employing this novel junction to realize a capacitively shunted qubit that we call flowermon. The d-wave nature of the order parameter endows the flowermon with inherent protection against charge-noise-induced relaxation and quasiparticle-induced dissipation. This inherently protected qubit paves the way to a new class of high-coherence hybrid superconducting quantum devices based on unconventional superconductors.
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Affiliation(s)
- Valentina Brosco
- Institute for Complex Systems (ISC) Consiglio Nazionale delle Ricerche and Physics Department University of Rome, "La Sapienza," Piazzale Aldo Moro, 2, 00185 Roma, Italy
- Centro Ricerche Enrico Fermi, Piazza del Viminale, 1, I-00184 Rome, Italy
| | - Giuseppe Serpico
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Department of Physics, University of Naples Federico II, Via Cintia, Naples 80126, Italy
| | - Valerii Vinokur
- Terra Quantum AG, Kornhausstrasse 25, CH-9000 St. Gallen, Switzerland
- Physics Department, CUNY, City College of City University of New York, 160 Convent Avenue, New York, New York 10031, USA
| | - Nicola Poccia
- Leibniz Institute for Solid State and Materials Science Dresden (IFW Dresden), 01069 Dresden, Germany
| | - Uri Vool
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
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8
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Wesdorp JJ, Grünhaupt L, Vaartjes A, Pita-Vidal M, Bargerbos A, Splitthoff LJ, Krogstrup P, van Heck B, de Lange G. Dynamical Polarization of the Fermion Parity in a Nanowire Josephson Junction. PHYSICAL REVIEW LETTERS 2023; 131:117001. [PMID: 37774257 DOI: 10.1103/physrevlett.131.117001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 01/22/2023] [Accepted: 07/14/2023] [Indexed: 10/01/2023]
Abstract
Josephson junctions in InAs nanowires proximitized with an Al shell can host gate-tunable Andreev bound states. Depending on the bound state occupation, the fermion parity of the junction can be even or odd. Coherent control of Andreev bound states has recently been achieved within each parity sector, but it is impeded by incoherent parity switches due to excess quasiparticles in the superconducting environment. Here, we show that we can polarize the fermion parity dynamically using microwave pulses by embedding the junction in a superconducting LC resonator. We demonstrate polarization up to 94%±1% (89%±1%) for the even (odd) parity as verified by single shot parity readout. Finally, we apply this scheme to probe the flux-dependent transition spectrum of the even or odd parity sector selectively, without any postprocessing or heralding.
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Affiliation(s)
- J J Wesdorp
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ, Delft, Netherlands
| | - L Grünhaupt
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ, Delft, Netherlands
| | - A Vaartjes
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ, Delft, Netherlands
| | - M Pita-Vidal
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ, Delft, Netherlands
| | - A Bargerbos
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ, Delft, Netherlands
| | - L J Splitthoff
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ, Delft, Netherlands
| | - P Krogstrup
- NNF Quantum Computing Programme, Niels Bohr Institute, University of Copenhagen, Denmark
| | - B van Heck
- Microsoft Quantum Lab Delft, 2628 CJ, Delft, Netherlands
- Leiden Institute of Physics, Universiteit Leiden, Niels Bohrweg 2, 2333 CA Leiden, Netherlands
- Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Roma, Italy
| | - G de Lange
- Microsoft Quantum Lab Delft, 2628 CJ, Delft, Netherlands
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9
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Lucas M, Danilov AV, Levitin LV, Jayaraman A, Casey AJ, Faoro L, Tzalenchuk AY, Kubatkin SE, Saunders J, de Graaf SE. Quantum bath suppression in a superconducting circuit by immersion cooling. Nat Commun 2023; 14:3522. [PMID: 37316500 DOI: 10.1038/s41467-023-39249-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 06/02/2023] [Indexed: 06/16/2023] Open
Abstract
Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at T ≈ 50 mK - far above the refrigerator base temperature. This is for example reflected in the thermal state population of qubits, in excess numbers of quasiparticles, and polarisation of surface spins - factors contributing to reduced coherence. We demonstrate how to remove this thermal constraint by operating a circuit immersed in liquid 3He. This allows to efficiently cool the decohering environment of a superconducting resonator, and we see a continuous change in measured physical quantities down to previously unexplored sub-mK temperatures. The 3He acts as a heat sink which increases the energy relaxation rate of the quantum bath coupled to the circuit a thousand times, yet the suppressed bath does not introduce additional circuit losses or noise. Such quantum bath suppression can reduce decoherence in quantum circuits and opens a route for both thermal and coherence management in quantum processors.
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Affiliation(s)
- M Lucas
- Physics Department, Royal Holloway University of London, Egham, UK
| | - A V Danilov
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - L V Levitin
- Physics Department, Royal Holloway University of London, Egham, UK
| | - A Jayaraman
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - A J Casey
- Physics Department, Royal Holloway University of London, Egham, UK
| | - L Faoro
- Google Quantum AI, Google Research, Mountain View, CA, USA
| | - A Ya Tzalenchuk
- Physics Department, Royal Holloway University of London, Egham, UK
- National Physical Laboratory, Teddington, TW11 0LW, UK
| | - S E Kubatkin
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
| | - J Saunders
- Physics Department, Royal Holloway University of London, Egham, UK
| | - S E de Graaf
- National Physical Laboratory, Teddington, TW11 0LW, UK.
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10
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Vettoliere A, Satariano R, Ferraiuolo R, Di Palma L, Ahmad HG, Ausanio G, Pepe GP, Tafuri F, Massarotti D, Montemurro D, Granata C, Parlato L. High-Quality Ferromagnetic Josephson Junctions Based on Aluminum Electrodes. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12234155. [PMID: 36500778 PMCID: PMC9736349 DOI: 10.3390/nano12234155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 06/12/2023]
Abstract
Aluminum Josephson junctions are the building blocks for the realization of superconducting quantum bits. Attention has been also paid to hybrid ferromagnetic Josephson junctions, which allow switching between different magnetic states, making them interesting for applications such as cryogenic memories, single-photon detectors, and spintronics. In this paper, we report on the fabrication and characterization of high-quality ferromagnetic Josephson junctions based on aluminum technology. We employed an innovative fabrication process inspired by niobium-based technology, allowing us to obtain very high-quality hybrid aluminum Josephson junctions; thus, supporting the use of ferromagnetic Josephson junctions in advanced quantum circuits. The fabrication process is described in detail and the main DC transport properties at low temperatures (current-voltage characteristic, critical current as a function of the temperature, and the external magnetic field) are reported. Here, we illustrate in detail the fabrication process, as well as the main DC transport properties at low temperatures (current-voltage characteristic, critical current as a function of the temperature, and the external magnetic field).
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Affiliation(s)
- Antonio Vettoliere
- Consiglio Nazionale delle Ricerche—ISASI, Via Campi Flegrei 34, I-80078 Pozzuoli, Italy
| | - Roberta Satariano
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
| | - Raffaella Ferraiuolo
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Luigi Di Palma
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Halima Giovanna Ahmad
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
| | - Giovanni Ausanio
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Giovanni Piero Pepe
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Francesco Tafuri
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—Istituto Nazionale di Ottica (CNR-INO), Largo Enrico Fermi 6, I-50125 Florence, Italy
| | - Davide Massarotti
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
| | - Domenico Montemurro
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Carmine Granata
- Consiglio Nazionale delle Ricerche—ISASI, Via Campi Flegrei 34, I-80078 Pozzuoli, Italy
| | - Loredana Parlato
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
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11
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Mi X, Sonner M, Niu MY, Lee KW, Foxen B, Acharya R, Aleiner I, Andersen TI, Arute F, Arya K, Asfaw A, Atalaya J, Bardin JC, Basso J, Bengtsson A, Bortoli G, Bourassa A, Brill L, Broughton M, Buckley BB, Buell DA, Burkett B, Bushnell N, Chen Z, Chiaro B, Collins R, Conner P, Courtney W, Crook AL, Debroy DM, Demura S, Dunsworth A, Eppens D, Erickson C, Faoro L, Farhi E, Fatemi R, Flores L, Forati E, Fowler AG, Giang W, Gidney C, Gilboa D, Giustina M, Dau AG, Gross JA, Habegger S, Harrigan MP, Hoffmann M, Hong S, Huang T, Huff A, Huggins WJ, Ioffe LB, Isakov SV, Iveland J, Jeffrey E, Jiang Z, Jones C, Kafri D, Kechedzhi K, Khattar T, Kim S, Kitaev AY, Klimov PV, Klots AR, Korotkov AN, Kostritsa F, Kreikebaum JM, Landhuis D, Laptev P, Lau KM, Lee J, Laws L, Liu W, Locharla A, Martin O, McClean JR, McEwen M, Meurer Costa B, Miao KC, Mohseni M, Montazeri S, Morvan A, Mount E, Mruczkiewicz W, Naaman O, Neeley M, Neill C, Newman M, O’Brien TE, Opremcak A, Petukhov A, Potter R, Quintana C, Rubin NC, Saei N, Sank D, Sankaragomathi K, Satzinger KJ, Schuster C, Shearn MJ, Shvarts V, Strain D, Su Y, Szalay M, Vidal G, Villalonga B, Vollgraff-Heidweiller C, White T, Yao Z, Yeh P, Yoo J, Zalcman A, Zhang Y, Zhu N, Neven H, Bacon D, Hilton J, Lucero E, Babbush R, Boixo S, Megrant A, Chen Y, Kelly J, Smelyanskiy V, Abanin DA, Roushan P. Noise-resilient edge modes on a chain of superconducting qubits. Science 2022; 378:785-790. [DOI: 10.1126/science.abq5769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with
ℤ
2
parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.
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Affiliation(s)
- X. Mi
- Google Research, Mountain View, CA, USA
| | - M. Sonner
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
| | - M. Y. Niu
- Google Research, Mountain View, CA, USA
| | - K. W. Lee
- Google Research, Mountain View, CA, USA
| | - B. Foxen
- Google Research, Mountain View, CA, USA
| | | | | | | | - F. Arute
- Google Research, Mountain View, CA, USA
| | - K. Arya
- Google Research, Mountain View, CA, USA
| | - A. Asfaw
- Google Research, Mountain View, CA, USA
| | | | - J. C. Bardin
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA, USA
| | - J. Basso
- Google Research, Mountain View, CA, USA
| | | | | | | | - L. Brill
- Google Research, Mountain View, CA, USA
| | | | | | | | | | | | - Z. Chen
- Google Research, Mountain View, CA, USA
| | - B. Chiaro
- Google Research, Mountain View, CA, USA
| | | | - P. Conner
- Google Research, Mountain View, CA, USA
| | | | | | | | - S. Demura
- Google Research, Mountain View, CA, USA
| | | | - D. Eppens
- Google Research, Mountain View, CA, USA
| | | | - L. Faoro
- Google Research, Mountain View, CA, USA
| | - E. Farhi
- Google Research, Mountain View, CA, USA
| | - R. Fatemi
- Google Research, Mountain View, CA, USA
| | - L. Flores
- Google Research, Mountain View, CA, USA
| | - E. Forati
- Google Research, Mountain View, CA, USA
| | | | - W. Giang
- Google Research, Mountain View, CA, USA
| | - C. Gidney
- Google Research, Mountain View, CA, USA
| | - D. Gilboa
- Google Research, Mountain View, CA, USA
| | | | - A. G. Dau
- Google Research, Mountain View, CA, USA
| | | | | | | | | | - S. Hong
- Google Research, Mountain View, CA, USA
| | - T. Huang
- Google Research, Mountain View, CA, USA
| | - A. Huff
- Google Research, Mountain View, CA, USA
| | | | | | | | | | | | - Z. Jiang
- Google Research, Mountain View, CA, USA
| | - C. Jones
- Google Research, Mountain View, CA, USA
| | - D. Kafri
- Google Research, Mountain View, CA, USA
| | | | | | - S. Kim
- Google Research, Mountain View, CA, USA
| | - A. Y. Kitaev
- Google Research, Mountain View, CA, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, CA, USA
| | | | | | - A. N. Korotkov
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | | | | | | | - P. Laptev
- Google Research, Mountain View, CA, USA
| | - K.-M. Lau
- Google Research, Mountain View, CA, USA
| | - J. Lee
- Google Research, Mountain View, CA, USA
| | - L. Laws
- Google Research, Mountain View, CA, USA
| | - W. Liu
- Google Research, Mountain View, CA, USA
| | | | - O. Martin
- Google Research, Mountain View, CA, USA
| | | | - M. McEwen
- Google Research, Mountain View, CA, USA
- Department of Physics, University of California, Santa Barbara, CA, USA
| | | | | | | | | | - A. Morvan
- Google Research, Mountain View, CA, USA
| | - E. Mount
- Google Research, Mountain View, CA, USA
| | | | - O. Naaman
- Google Research, Mountain View, CA, USA
| | - M. Neeley
- Google Research, Mountain View, CA, USA
| | - C. Neill
- Google Research, Mountain View, CA, USA
| | - M. Newman
- Google Research, Mountain View, CA, USA
| | | | | | | | - R. Potter
- Google Research, Mountain View, CA, USA
| | | | | | - N. Saei
- Google Research, Mountain View, CA, USA
| | - D. Sank
- Google Research, Mountain View, CA, USA
| | | | | | | | | | | | - D. Strain
- Google Research, Mountain View, CA, USA
| | - Y. Su
- Google Research, Mountain View, CA, USA
| | - M. Szalay
- Google Research, Mountain View, CA, USA
| | - G. Vidal
- Google Research, Mountain View, CA, USA
| | | | | | - T. White
- Google Research, Mountain View, CA, USA
| | - Z. Yao
- Google Research, Mountain View, CA, USA
| | - P. Yeh
- Google Research, Mountain View, CA, USA
| | - J. Yoo
- Google Research, Mountain View, CA, USA
| | | | - Y. Zhang
- Google Research, Mountain View, CA, USA
| | - N. Zhu
- Google Research, Mountain View, CA, USA
| | - H. Neven
- Google Research, Mountain View, CA, USA
| | - D. Bacon
- Google Research, Mountain View, CA, USA
| | - J. Hilton
- Google Research, Mountain View, CA, USA
| | - E. Lucero
- Google Research, Mountain View, CA, USA
| | | | - S. Boixo
- Google Research, Mountain View, CA, USA
| | | | - Y. Chen
- Google Research, Mountain View, CA, USA
| | - J. Kelly
- Google Research, Mountain View, CA, USA
| | | | - D. A. Abanin
- Google Research, Mountain View, CA, USA
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
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12
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Phonon downconversion to suppress correlated errors in superconducting qubits. Nat Commun 2022; 13:6425. [PMID: 36307415 DOI: 10.1038/s41467-022-33997-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/07/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum error correction can preserve quantum information in the presence of local errors, but correlated errors are fatal. For superconducting qubits, high-energy particle impacts from background radioactivity produce energetic phonons that travel throughout the substrate and create excitations above the superconducting ground state, known as quasiparticles, which can poison all qubits on the chip. We use normal metal reservoirs on the chip back side to downconvert phonons to low energies where they can no longer poison qubits. We introduce a pump-probe scheme involving controlled injection of pair-breaking phonons into the qubit chips. We examine quasiparticle poisoning on chips with and without back-side metallization and demonstrate a reduction in the flux of pair-breaking phonons by over a factor of 20. We use a Ramsey interferometer scheme to simultaneously monitor quasiparticle parity on three qubits for each chip and observe a two-order of magnitude reduction in correlated poisoning due to background radiation.
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13
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Islam S, Shamim S, Ghosh A. Benchmarking Noise and Dephasing in Emerging Electrical Materials for Quantum Technologies. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2109671. [PMID: 35545231 DOI: 10.1002/adma.202109671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 05/01/2022] [Indexed: 06/15/2023]
Abstract
As quantum technologies develop, a specific class of electrically conducting materials is rapidly gaining interest because they not only form the core quantum-enabled elements in superconducting qubits, semiconductor nanostructures, or sensing devices, but also the peripheral circuitry. The phase coherence of the electronic wave function in these emerging materials will be crucial when incorporated in the quantum architecture. The loss of phase memory, or dephasing, occurs when a quantum system interacts with the fluctuations in the local electromagnetic environment, which manifests in "noise" in the electrical conductivity. Hence, characterizing these materials and devices therefrom, for quantum applications, requires evaluation of both dephasing and noise, although there are very few materials where these properties are investigated simultaneously. Here, the available data on magnetotransport and low-frequency fluctuations in electrical conductivity are reviewed to benchmark the dephasing and noise. The focus is on new materials that are of direct interest to quantum technologies. The physical processes causing dephasing and noise in these systems are elaborated, the impact of both intrinsic and extrinsic parameters from materials synthesis and devices realization are evaluated, and it is hoped that a clearer pathway to design and characterize both material and devices for quantum applications is thus provided.
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Affiliation(s)
- Saurav Islam
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
| | - Saquib Shamim
- Experimentelle Physik III, Physikalisches Institut, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Topological Insulators, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Arindam Ghosh
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru, 560012, India
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14
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Spring PA, Cao S, Tsunoda T, Campanaro G, Fasciati S, Wills J, Bakr M, Chidambaram V, Shteynas B, Carpenter L, Gow P, Gates J, Vlastakis B, Leek PJ. High coherence and low cross-talk in a tileable 3D integrated superconducting circuit architecture. SCIENCE ADVANCES 2022; 8:eabl6698. [PMID: 35452292 PMCID: PMC9032975 DOI: 10.1126/sciadv.abl6698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
We report high qubit coherence as well as low cross-talk and single-qubit gate errors in a superconducting circuit architecture that promises to be tileable to two-dimensional (2D) lattices of qubits. The architecture integrates an inductively shunted cavity enclosure into a design featuring nongalvanic out-of-plane control wiring and qubits and resonators fabricated on opposing sides of a substrate. The proof-of-principle device features four uncoupled transmon qubits and exhibits average energy relaxation times T1 = 149(38) μs, pure echoed dephasing times Tϕ,e = 189(34) μs, and single-qubit gate fidelities F = 99.982(4)% as measured by simultaneous randomized benchmarking. The 3D integrated nature of the control wiring means that qubits will remain addressable as the architecture is tiled to form larger qubit lattices. Band structure simulations are used to predict that the tiled enclosure will still provide a clean electromagnetic environment to enclosed qubits at arbitrary scale.
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Affiliation(s)
- Peter A. Spring
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Shuxiang Cao
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Takahiro Tsunoda
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Giulio Campanaro
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Simone Fasciati
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - James Wills
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Mustafa Bakr
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Vivek Chidambaram
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Boris Shteynas
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Lewis Carpenter
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK
| | - Paul Gow
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK
| | - James Gates
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK
| | - Brian Vlastakis
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Peter J. Leek
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
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15
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Wilen CD, Abdullah S, Kurinsky NA, Stanford C, Cardani L, D'Imperio G, Tomei C, Faoro L, Ioffe LB, Liu CH, Opremcak A, Christensen BG, DuBois JL, McDermott R. Correlated charge noise and relaxation errors in superconducting qubits. Nature 2021; 594:369-373. [PMID: 34135523 DOI: 10.1038/s41586-021-03557-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/15/2021] [Indexed: 11/09/2022]
Abstract
The central challenge in building a quantum computer is error correction. Unlike classical bits, which are susceptible to only one type of error, quantum bits (qubits) are susceptible to two types of error, corresponding to flips of the qubit state about the X and Z directions. Although the Heisenberg uncertainty principle precludes simultaneous monitoring of X- and Z-flips on a single qubit, it is possible to encode quantum information in large arrays of entangled qubits that enable accurate monitoring of all errors in the system, provided that the error rate is low1. Another crucial requirement is that errors cannot be correlated. Here we characterize a superconducting multiqubit circuit and find that charge noise in the chip is highly correlated on a length scale over 600 micrometres; moreover, discrete charge jumps are accompanied by a strong transient reduction of qubit energy relaxation time across the millimetre-scale chip. The resulting correlated errors are explained in terms of the charging event and phonon-mediated quasiparticle generation associated with absorption of γ-rays and cosmic-ray muons in the qubit substrate. Robust quantum error correction will require the development of mitigation strategies to protect multiqubit arrays from correlated errors due to particle impacts.
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Affiliation(s)
- C D Wilen
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA.
| | - S Abdullah
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - N A Kurinsky
- Fermi National Accelerator Laboratory, Center for Particle Astrophysics, Batavia, IL, USA.,Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL, USA
| | - C Stanford
- Department of Physics, Stanford University, Stanford, CA, USA
| | | | | | - C Tomei
- INFN Sezione di Roma, Rome, Italy
| | - L Faoro
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA.,Sorbonne Université, Laboratoire de Physique Théorique et Hautes Energies, Paris, France
| | | | - C H Liu
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - A Opremcak
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - B G Christensen
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - J L DuBois
- Physics Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - R McDermott
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA.
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16
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Cardani L, Valenti F, Casali N, Catelani G, Charpentier T, Clemenza M, Colantoni I, Cruciani A, D'Imperio G, Gironi L, Grünhaupt L, Gusenkova D, Henriques F, Lagoin M, Martinez M, Pettinari G, Rusconi C, Sander O, Tomei C, Ustinov AV, Weber M, Wernsdorfer W, Vignati M, Pirro S, Pop IM. Reducing the impact of radioactivity on quantum circuits in a deep-underground facility. Nat Commun 2021; 12:2733. [PMID: 33980835 PMCID: PMC8115287 DOI: 10.1038/s41467-021-23032-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/13/2021] [Indexed: 11/29/2022] Open
Abstract
As quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor thirty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware.
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Affiliation(s)
| | - F Valenti
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- IPE, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - N Casali
- INFN Sezione di Roma, Roma, Italy
| | - G Catelani
- JARA Institute for Quantum Information, Forschungszentrum Jülich, Jülich, Germany
| | - T Charpentier
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - M Clemenza
- Dipartimento di Fisica, Università di Milano - Bicocca, Milano, Italy
- INFN Sezione di Milano - Bicocca, Milano, Italy
| | - I Colantoni
- INFN Sezione di Roma, Roma, Italy
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, c/o Dip. Fisica, Sapienza Università di Roma, Roma, Italy
| | | | | | - L Gironi
- Dipartimento di Fisica, Università di Milano - Bicocca, Milano, Italy
- INFN Sezione di Milano - Bicocca, Milano, Italy
| | - L Grünhaupt
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - D Gusenkova
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - F Henriques
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - M Lagoin
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - M Martinez
- Fundación ARAID and Centro de Astropartículas y Física de Altas Energías, Universidad de Zaragoza, Zaragoza, Spain
| | - G Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council, Rome, Italy
| | - C Rusconi
- INFN Laboratori Nazionali del Gran Sasso, Assergi, Italy
- Department of Physics and Astronomy, University of South Carolina, Columbia, USA
| | - O Sander
- IPE, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - C Tomei
- INFN Sezione di Roma, Roma, Italy
| | - A V Ustinov
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- National University of Science and Technology MISIS, Moscow, Russia
- Russian Quantum Center, Skolkovo, Moscow, Russia
| | - M Weber
- IPE, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - W Wernsdorfer
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- Institut Néel, CNRS and Université Joseph Fourier, Grenoble, France
| | - M Vignati
- INFN Sezione di Roma, Roma, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, Roma, Italy
| | - S Pirro
- INFN Laboratori Nazionali del Gran Sasso, Assergi, Italy
| | - I M Pop
- PHI, Karlsruhe Institute of Technology, Karlsruhe, Germany.
- IQMT, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
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17
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Walsh ED, Jung W, Lee GH, Efetov DK, Wu BI, Huang KF, Ohki TA, Taniguchi T, Watanabe K, Kim P, Englund D, Fong KC. Josephson junction infrared single-photon detector. Science 2021; 372:409-412. [PMID: 33888641 DOI: 10.1126/science.abf5539] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/22/2021] [Indexed: 11/02/2022]
Abstract
Josephson junctions are superconducting devices used as high-sensitivity magnetometers and voltage amplifiers as well as the basis of high-performance cryogenic computers and superconducting quantum computers. Although device performance can be degraded by the generation of quasiparticles formed from broken Cooper pairs, this phenomenon also opens opportunities to sensitively detect electromagnetic radiation. We demonstrate single near-infrared photon detection by coupling photons to the localized surface plasmons of a graphene-based Josephson junction. Using the photon-induced switching statistics of the current-biased device, we reveal the critical role of quasiparticles generated by the absorbed photon in the detection mechanism. The photon sensitivity will enable a high-speed, low-power optical interconnect for future superconducting computing architectures.
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Affiliation(s)
- Evan D Walsh
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Woochan Jung
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Dmitri K Efetov
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Bae-Ian Wu
- Air Force Research Laboratory, Wright-Patterson AFB, OH 45433, USA
| | - K-F Huang
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Thomas A Ohki
- Raytheon BBN Technologies, Quantum Engineering and Computing Group Cambridge, MA 02138, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Dirk Englund
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kin Chung Fong
- Raytheon BBN Technologies, Quantum Engineering and Computing Group Cambridge, MA 02138, USA.
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18
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de Leon NP, Itoh KM, Kim D, Mehta KK, Northup TE, Paik H, Palmer BS, Samarth N, Sangtawesin S, Steuerman DW. Materials challenges and opportunities for quantum computing hardware. Science 2021; 372:372/6539/eabb2823. [PMID: 33859004 DOI: 10.1126/science.abb2823] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Quantum computing hardware technologies have advanced during the past two decades, with the goal of building systems that can solve problems that are intractable on classical computers. The ability to realize large-scale systems depends on major advances in materials science, materials engineering, and new fabrication techniques. We identify key materials challenges that currently limit progress in five quantum computing hardware platforms, propose how to tackle these problems, and discuss some new areas for exploration. Addressing these materials challenges will require scientists and engineers to work together to create new, interdisciplinary approaches beyond the current boundaries of the quantum computing field.
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Affiliation(s)
- Nathalie P de Leon
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Dohun Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Karan K Mehta
- Department of Physics, Institute for Quantum Electronics, ETH Zürich, 8092 Zürich, Switzerland
| | - Tracy E Northup
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - Hanhee Paik
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598, USA.
| | - B S Palmer
- Laboratory for Physical Sciences, University of Maryland, College Park, MD 20740, USA.,Quantum Materials Center, University of Maryland, College Park, MD 20742, USA
| | - N Samarth
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sorawis Sangtawesin
- School of Physics and Center of Excellence in Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - D W Steuerman
- Kavli Foundation, 5715 Mesmer Avenue, Los Angeles, CA 90230, USA
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19
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Dixit AV, Chakram S, He K, Agrawal A, Naik RK, Schuster DI, Chou A. Searching for Dark Matter with a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2021; 126:141302. [PMID: 33891438 DOI: 10.1103/physrevlett.126.141302] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/05/2021] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Detection mechanisms for low mass bosonic dark matter candidates, such as the axion or hidden photon, leverage potential interactions with electromagnetic fields, whereby the dark matter (of unknown mass) on rare occasion converts into a single photon. Current dark matter searches operating at microwave frequencies use a resonant cavity to coherently accumulate the field sourced by the dark matter and a near standard quantum limited (SQL) linear amplifier to read out the cavity signal. To further increase sensitivity to the dark matter signal, sub-SQL detection techniques are required. Here we report the development of a novel microwave photon counting technique and a new exclusion limit on hidden photon dark matter. We operate a superconducting qubit to make repeated quantum nondemolition measurements of cavity photons and apply a hidden Markov model analysis to reduce the noise to 15.7 dB below the quantum limit, with overall detector performance limited by a residual background of real photons. With the present device, we perform a hidden photon search and constrain the kinetic mixing angle to ε≤1.68×10^{-15} in a band around 6.011 GHz (24.86 μeV) with an integration time of 8.33 s. This demonstrated noise reduction technique enables future dark matter searches to be sped up by a factor of 1,300. By coupling a qubit to an arbitrary quantum sensor, more general sub-SQL metrology is possible with the techniques presented in this Letter.
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Affiliation(s)
- Akash V Dixit
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Srivatsan Chakram
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Kevin He
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Ankur Agrawal
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Ravi K Naik
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
| | - David I Schuster
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Aaron Chou
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
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20
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Alegria LD, Bøttcher CGL, Saydjari AK, Pierce AT, Lee SH, Harvey SP, Vool U, Yacoby A. High-energy quasiparticle injection into mesoscopic superconductors. NATURE NANOTECHNOLOGY 2021; 16:404-408. [PMID: 33462428 DOI: 10.1038/s41565-020-00834-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
At non-zero temperatures, superconductors contain excitations known as Bogoliubov quasiparticles (QPs). The mesoscopic dynamics of QPs inform the design of quantum information processors, among other devices. Knowledge of these dynamics stems from experiments in which QPs are injected in a controlled fashion, typically at energies comparable to the pairing energy1-5. Here we perform tunnel spectroscopy of a mesoscopic superconductor under high electric fields. We observe QP injection due to field-emitted electrons with 106 times the pairing energy, an unexplored regime of QP dynamics. Upon application of a gate voltage, the QP injection decreases the critical current and, at sufficiently high electric field, a field-emission current (<0.1 nA in our device) switches the mesoscopic superconductor into the normal state, consistent with earlier observations6. We expect that high-energy injection will be useful for developing QP-tolerant quantum information processors, will allow rapid control of resonator quality factors and will enable the design of electric-field-controlled superconducting devices with new functionality.
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Affiliation(s)
- Loren D Alegria
- Department of Physics, Harvard University, Cambridge, MA, USA.
| | | | | | - Andrew T Pierce
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Seung Hwan Lee
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Uri Vool
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Amir Yacoby
- Department of Physics, Harvard University, Cambridge, MA, USA
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21
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New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds. Nat Commun 2021; 12:1779. [PMID: 33741989 PMCID: PMC7979772 DOI: 10.1038/s41467-021-22030-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 02/24/2021] [Indexed: 11/13/2022] Open
Abstract
The superconducting transmon qubit is a leading platform for quantum computing and quantum science. Building large, useful quantum systems based on transmon qubits will require significant improvements in qubit relaxation and coherence times, which are orders of magnitude shorter than limits imposed by bulk properties of the constituent materials. This indicates that relaxation likely originates from uncontrolled surfaces, interfaces, and contaminants. Previous efforts to improve qubit lifetimes have focused primarily on designs that minimize contributions from surfaces. However, significant improvements in the lifetime of two-dimensional transmon qubits have remained elusive for several years. Here, we fabricate two-dimensional transmon qubits that have both lifetimes and coherence times with dynamical decoupling exceeding 0.3 milliseconds by replacing niobium with tantalum in the device. We have observed increased lifetimes for seventeen devices, indicating that these material improvements are robust, paving the way for higher gate fidelities in multi-qubit processors. Quantum computers based on superconducting transmon qubits are limited by single qubit lifetimes and coherence times, which are orders of magnitude shorter than limits imposed by bulk material properties. Here, the authors fabricate two-dimensional transmon qubits with both lifetimes and coherence times longer than 0.3 milliseconds by replacing niobium with tantalum in the device.
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22
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Karzig T, Cole WS, Pikulin DI. Quasiparticle Poisoning of Majorana Qubits. PHYSICAL REVIEW LETTERS 2021; 126:057702. [PMID: 33605758 DOI: 10.1103/physrevlett.126.057702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/17/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
Qubits based on Majorana zero modes are a promising path towards topological quantum computing. Such qubits, though, are susceptible to quasiparticle poisoning which does not have to be small by topological argument. We study the main sources of the quasiparticle poisoning relevant for realistic devices-nonequilibrium above-gap quasiparticles and equilibrium localized subgap states. Depending on the parameters of the system and the architecture of the qubit either of these sources can dominate the qubit decoherence. However, we find in contrast to naive estimates that in moderately disordered, floating Majorana islands the quasiparticle poisoning can have timescales exceeding seconds.
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Affiliation(s)
- Torsten Karzig
- Microsoft Quantum, Station Q, Santa Barbara, California 93106, USA
| | - William S Cole
- Microsoft Quantum, Station Q, Santa Barbara, California 93106, USA
| | - Dmitry I Pikulin
- Microsoft Quantum, Station Q, Santa Barbara, California 93106, USA
- Microsoft Quantum, Redmond, Washington 98052, USA
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23
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Magnard P, Storz S, Kurpiers P, Schär J, Marxer F, Lütolf J, Walter T, Besse JC, Gabureac M, Reuer K, Akin A, Royer B, Blais A, Wallraff A. Microwave Quantum Link between Superconducting Circuits Housed in Spatially Separated Cryogenic Systems. PHYSICAL REVIEW LETTERS 2020; 125:260502. [PMID: 33449744 DOI: 10.1103/physrevlett.125.260502] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/16/2020] [Indexed: 05/26/2023]
Abstract
Superconducting circuits are a strong contender for realizing quantum computing systems and are also successfully used to study quantum optics and hybrid quantum systems. However, their cryogenic operation temperatures and the current lack of coherence-preserving microwave-to-optical conversion solutions have hindered the realization of superconducting quantum networks spanning different cryogenic systems or larger distances. Here, we report the successful operation of a cryogenic waveguide coherently linking transmon qubits located in two dilution refrigerators separated by a physical distance of five meters. We transfer qubit states and generate entanglement on demand with average transfer and target state fidelities of 85.8% and 79.5%, respectively, between the two nodes of this elementary network. Cryogenic microwave links provide an opportunity to scale up systems for quantum computing and create local area superconducting quantum communication networks over length scales of at least tens of meters.
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Affiliation(s)
- P Magnard
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Storz
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - P Kurpiers
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Schär
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - F Marxer
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Lütolf
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - T Walter
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J-C Besse
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M Gabureac
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - K Reuer
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Akin
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - B Royer
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - A Blais
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
- Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - A Wallraff
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
- Quantum Center, ETH Zürich, 8093 Zürich, Switzerland
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24
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de Graaf SE, Faoro L, Ioffe LB, Mahashabde S, Burnett JJ, Lindström T, Kubatkin SE, Danilov AV, Tzalenchuk AY. Two-level systems in superconducting quantum devices due to trapped quasiparticles. SCIENCE ADVANCES 2020; 6:eabc5055. [PMID: 33355127 PMCID: PMC11206451 DOI: 10.1126/sciadv.abc5055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
A major issue for the implementation of large-scale superconducting quantum circuits is the interaction with interfacial two-level system (TLS) defects that lead to qubit parameter fluctuations and relaxation. Another major challenge comes from nonequilibrium quasiparticles (QPs) that result in qubit relaxation and dephasing. Here, we reveal a previously unexplored decoherence mechanism in the form of a new type of TLS originating from trapped QPs, which can induce qubit relaxation. Using spectral, temporal, thermal, and magnetic field mapping of TLS-induced fluctuations in frequency tunable resonators, we identify a highly coherent subset of the general TLS population with a low reconfiguration temperature ∼300 mK and a nonuniform density of states. These properties can be understood if the TLS are formed by QPs trapped in shallow subgap states formed by spatial fluctutations of the superconducting order parameter. This implies that even very rare QP bursts will affect coherence over exponentially long time scales.
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Affiliation(s)
- S E de Graaf
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK.
| | - L Faoro
- Sorbonne Université, Laboratoire de Physique Théorique et Hautes Énergies, UMR 7589 CNRS, Tour 13, 5eme Etage, 4 Place Jussieu, F-75252 Paris 05, France
- Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - L B Ioffe
- Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA
- Google Inc., Venice, CA 90291, USA
| | - S Mahashabde
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296 Goteborg, Sweden
| | - J J Burnett
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
| | - T Lindström
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
| | - S E Kubatkin
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296 Goteborg, Sweden
| | - A V Danilov
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296 Goteborg, Sweden
| | - A Ya Tzalenchuk
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK
- Royal Holloway, University of London, Egham TW20 0EX, UK
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25
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Sabonis D, Erlandsson O, Kringhøj A, van Heck B, Larsen TW, Petkovic I, Krogstrup P, Petersson KD, Marcus CM. Destructive Little-Parks Effect in a Full-Shell Nanowire-Based Transmon. PHYSICAL REVIEW LETTERS 2020; 125:156804. [PMID: 33095630 DOI: 10.1103/physrevlett.125.156804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
A semiconductor transmon with an epitaxial Al shell fully surrounding an InAs nanowire core is investigated in the low E_{J}/E_{C} regime. Little-Parks oscillations as a function of flux along the hybrid wire axis are destructive, creating lobes of reentrant superconductivity separated by a metallic state at a half quantum of applied flux. In the first lobe, phase winding around the shell can induce topological superconductivity in the core. Coherent qubit operation is observed in both the zeroth and first lobes. Splitting of parity bands by coherent single-electron coupling across the junction is not resolved beyond line broadening, placing a bound on Majorana coupling, E_{M}/h<10 MHz, much smaller than the Josephson coupling E_{J}/h∼4.7 GHz.
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Affiliation(s)
- Deividas Sabonis
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Oscar Erlandsson
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Anders Kringhøj
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Bernard van Heck
- Microsoft Quantum Lab Delft, Delft University of Technology, 2600 GA Delft, Netherlands
| | - Thorvald W Larsen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ivana Petkovic
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Peter Krogstrup
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Materials Lab-Copenhagen, 2800 Lyngby, Denmark
| | - Karl D Petersson
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Charles M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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26
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McRae CRH, Wang H, Gao J, Vissers MR, Brecht T, Dunsworth A, Pappas DP, Mutus J. Materials loss measurements using superconducting microwave resonators. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:091101. [PMID: 33003823 DOI: 10.1063/5.0017378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
The performance of superconducting circuits for quantum computing is limited by materials losses. In particular, coherence times are typically bounded by two-level system (TLS) losses at single photon powers and millikelvin temperatures. The identification of low loss fabrication techniques, materials, and thin film dielectrics is critical to achieving scalable architectures for superconducting quantum computing. Superconducting microwave resonators provide a convenient qubit proxy for assessing performance and studying TLS loss and other mechanisms relevant to superconducting circuits such as non-equilibrium quasiparticles and magnetic flux vortices. In this review article, we provide an overview of considerations for designing accurate resonator experiments to characterize loss, including applicable types of losses, cryogenic setup, device design, and methods for extracting material and interface losses, summarizing techniques that have been evolving for over two decades. Results from measurements of a wide variety of materials and processes are also summarized. Finally, we present recommendations for the reporting of loss data from superconducting microwave resonators to facilitate materials comparisons across the field.
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Affiliation(s)
- C R H McRae
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - H Wang
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - J Gao
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - M R Vissers
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - T Brecht
- HRL Laboratories, Malibu, California 90265, USA
| | - A Dunsworth
- Google, Inc., Mountain View, California 94043, USA
| | - D P Pappas
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - J Mutus
- Boulder Cryogenic Quantum Testbed, University of Colorado, Boulder, Colorado 80309, USA
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27
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Meyer JS, Houzet M, Nazarov YV. Dynamical Spin Polarization of Excess Quasiparticles in Superconductors. PHYSICAL REVIEW LETTERS 2020; 125:097006. [PMID: 32915596 DOI: 10.1103/physrevlett.125.097006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
We show that the annihilation dynamics of excess quasiparticles in superconductors may result in the spontaneous formation of large spin-polarized clusters. This presents a novel scenario for spontaneous spin polarization. We estimate the relevant scales for aluminum, finding the feasibility of clusters with total spin S≃10^{4}ℏ that could be spread over microns. The fluctuation dynamics of such large spins may be detected by measuring the flux noise in a loop hosting a cluster.
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Affiliation(s)
- Julia S Meyer
- Univ. Grenoble Alpes, CEA, IRIG-Pheliqs, F-38000 Grenoble, France
| | - Manuel Houzet
- Univ. Grenoble Alpes, CEA, IRIG-Pheliqs, F-38000 Grenoble, France
| | - Yuli V Nazarov
- Kavli Institute of NanoScience, Delft University of Technology, Lorentzweg 1, NL-2628 CJ, Delft, Netherlands
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28
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Impact of ionizing radiation on superconducting qubit coherence. Nature 2020; 584:551-556. [DOI: 10.1038/s41586-020-2619-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 06/05/2020] [Indexed: 11/09/2022]
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29
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Petkovic I, Lollo A, Harris JGE. Phase-Slip Statistics of a Single Isolated Flux-Biased Superconducting Ring. PHYSICAL REVIEW LETTERS 2020; 125:067002. [PMID: 32845664 DOI: 10.1103/physrevlett.125.067002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
We describe measurements of the thermally activated transitions between fluxoid states of a single isolated superconducting ring. We compare these measurements with theoretical predictions in which all of the relevant parameters are determined via independent characterization of the same ring. This no-free-parameters comparison shows qualitative agreement over a wide range of temperatures. We discuss possible origins for the remaining discrepancies between the data and theory, in particular the choice of model for the superconducting order parameter's damping.
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Affiliation(s)
- I Petkovic
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06520, USA
| | - A Lollo
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06520, USA
| | - J G E Harris
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06520, USA
- Department of Applied Physics, Yale University, 15 Prospect Street, New Haven, Connecticut 06520, USA
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30
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Marín-Suárez M, Peltonen JT, Pekola JP. Active Quasiparticle Suppression in a Non-Equilibrium Superconductor. NANO LETTERS 2020; 20:5065-5071. [PMID: 32551699 PMCID: PMC7467774 DOI: 10.1021/acs.nanolett.0c01264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/09/2020] [Indexed: 06/11/2023]
Abstract
Quasiparticle (qp) poisoning is a major issue that impairs the operation of various superconducting devices. Even though these devices are often operated at temperatures well below the critical point where the number density of excitations is expected to be exponentially suppressed, their bare operation and stray microwave radiation excite the non-equilibrium qp's. Here we use voltage-biased superconducting junctions to demonstrate and quantify qp extraction in the turnstile operation of a superconductor-insulator-normal metal-insulator-superconductor single-electron transistor. In this operation regime, excitations are injected into the superconducting leads at a rate proportional to the driving frequency. We reach a reduction of density by an order of magnitude even for the highest injection rate of 2.4 × 108 qp's per second when extraction is turned on.
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Affiliation(s)
- Marco Marín-Suárez
- Pico group, QTF Centre of
Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland
| | - Joonas T. Peltonen
- Pico group, QTF Centre of
Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland
| | - Jukka P. Pekola
- Pico group, QTF Centre of
Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland
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31
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Kulikov A, Navarathna R, Fedorov A. Measuring Effective Temperatures of Qubits Using Correlations. PHYSICAL REVIEW LETTERS 2020; 124:240501. [PMID: 32639795 DOI: 10.1103/physrevlett.124.240501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
Initialization of a qubit in a pure state is a prerequisite for quantum computer operation. A plethora of ways to achieve this has been proposed in the last decade, from active reset protocols to advances in materials and shielding. An instrumental tool to evaluate those methods and develop new ones is the ability to measure the population of excited states with high precision and in a short period of time. In this Letter, we propose a new technique of finding the excited state population of a qubit using correlations between two sequential measurements. We experimentally implement the proposed technique using a circuit QED platform and compare its performance with previously developed ones. Unlike other techniques, our method does not require high-fidelity readout and does not involve the excited levels of the system outside of the qubit subspace. We experimentally demonstrated measurement of the spurious qubit population with accuracy of up to 0.01%. This accuracy enabled us to perform "temperature spectroscopy" of the qubit, which helps to shed light on decoherence sources.
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Affiliation(s)
- Anatoly Kulikov
- ARC Centre of Excellence for Engineered Quantum Systems, Queensland 4072, Australia
- School of Mathematics and Physics, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Rohit Navarathna
- ARC Centre of Excellence for Engineered Quantum Systems, Queensland 4072, Australia
- School of Mathematics and Physics, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Arkady Fedorov
- ARC Centre of Excellence for Engineered Quantum Systems, Queensland 4072, Australia
- School of Mathematics and Physics, University of Queensland, St Lucia, Queensland 4072, Australia
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32
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Houzet M, Serniak K, Catelani G, Devoret MH, Glazman LI. Photon-Assisted Charge-Parity Jumps in a Superconducting Qubit. PHYSICAL REVIEW LETTERS 2019; 123:107704. [PMID: 31573281 DOI: 10.1103/physrevlett.123.107704] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Indexed: 06/10/2023]
Abstract
We evaluate the rates of energy and phase relaxation of a superconducting qubit caused by stray photons with energy exceeding the threshold for breaking a Cooper pair. All channels of relaxation within this mechanism are associated with the change in the charge parity of the qubit, enabling the separation of the photon-assisted processes from other contributions to the relaxation rates. Among the signatures of the new mechanism is the same order of rates of the transitions in which a qubit loses or gains energy, which is in agreement with recent experiments. Our theory offers the possibility to characterize the electromagnetic environment of superconducting devices at the single-photon level for frequencies above the superconducting gap.
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Affiliation(s)
- M Houzet
- Univ. Grenoble Alpes, CEA, IRIG-Pheliqs, F-38000 Grenoble, France
| | - K Serniak
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - G Catelani
- JARA Institute for Quantum Information (PGI-11), Forschungszentrum Jülich, 52425 Jülich, Germany
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - M H Devoret
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - L I Glazman
- Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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