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Lecocq F, Ranzani L, Peterson GA, Cicak K, Jin XY, Simmonds RW, Teufel JD, Aumentado J. Efficient Qubit Measurement with a Nonreciprocal Microwave Amplifier. Phys Rev Lett 2021; 126:020502. [PMID: 33512236 DOI: 10.1103/physrevlett.126.020502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
The act of observing a quantum object fundamentally perturbs its state, resulting in a random walk toward an eigenstate of the measurement operator. Ideally, the measurement is responsible for all dephasing of the quantum state. In practice, imperfections in the measurement apparatus limit or corrupt the flow of information required for quantum feedback protocols, an effect quantified by the measurement efficiency. Here, we demonstrate the efficient measurement of a superconducting qubit using a nonreciprocal parametric amplifier to directly monitor the microwave field of a readout cavity. By mitigating the losses between the cavity and the amplifier, we achieve a measurement efficiency of (72±4)%. The directionality of the amplifier protects the readout cavity and qubit from excess backaction caused by amplified vacuum fluctuations. In addition to providing tools for further improving the fidelity of strong projective measurement, this work creates a test bed for the experimental study of ideal weak measurements, and it opens the way toward quantum feedback protocols based on weak measurement such as state stabilization or error correction.
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Affiliation(s)
- F Lecocq
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, 2000 Colorado Avenue, Boulder, Colorado 80309, USA
| | - L Ranzani
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, USA
| | - G A Peterson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, 2000 Colorado Avenue, Boulder, Colorado 80309, USA
| | - K Cicak
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - X Y Jin
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, 2000 Colorado Avenue, Boulder, Colorado 80309, USA
| | - R W Simmonds
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J D Teufel
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J Aumentado
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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2
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Peterson GA, Kotler S, Lecocq F, Cicak K, Jin XY, Simmonds RW, Aumentado J, Teufel JD. Ultrastrong Parametric Coupling between a Superconducting Cavity and a Mechanical Resonator. Phys Rev Lett 2019; 123:247701. [PMID: 31922827 DOI: 10.1103/physrevlett.123.247701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Indexed: 06/10/2023]
Abstract
We present a new optomechanical device where the motion of a micromechanical membrane couples to a microwave resonance of a three-dimensional superconducting cavity. With this architecture, we realize ultrastrong parametric coupling, where the coupling not only exceeds the dissipation in the system but also rivals the mechanical frequency itself. In this regime, the optomechanical interaction induces a frequency splitting between the hybridized normal modes that reaches 88% of the bare mechanical frequency, limited by the fundamental parametric instability. The coupling also exceeds the mechanical thermal decoherence rate, enabling new applications in ultrafast quantum state transfer and entanglement generation.
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Affiliation(s)
- G A Peterson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - S Kotler
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - F Lecocq
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - K Cicak
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - X Y Jin
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - R W Simmonds
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J Aumentado
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J D Teufel
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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Menke T, Burns PS, Higginbotham AP, Kampel NS, Peterson RW, Cicak K, Simmonds RW, Regal CA, Lehnert KW. Reconfigurable re-entrant cavity for wireless coupling to an electro-optomechanical device. Rev Sci Instrum 2017; 88:094701. [PMID: 28964202 DOI: 10.1063/1.5000973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/20/2017] [Indexed: 06/07/2023]
Abstract
An electro-optomechanical device capable of microwave-to-optics conversion has recently been demonstrated, with the vision of enabling optical networks of superconducting qubits. Here we present an improved converter design that uses a three-dimensional microwave cavity for coupling between the microwave transmission line and an integrated LC resonator on the converter chip. The new design simplifies the optical assembly and decouples it from the microwave part of the setup. Experimental demonstrations show that the modular device assembly allows us to flexibly tune the microwave coupling to the converter chip while maintaining small loss. We also find that electromechanical experiments are not impacted by the additional microwave cavity. Our design is compatible with a high-finesse optical cavity and will improve optical performance.
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Affiliation(s)
- T Menke
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - P S Burns
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - A P Higginbotham
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - N S Kampel
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - R W Peterson
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - K Cicak
- National Institute of Standards and Technology (NIST), Boulder, Colorado 80305, USA
| | - R W Simmonds
- National Institute of Standards and Technology (NIST), Boulder, Colorado 80305, USA
| | - C A Regal
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - K W Lehnert
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
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Lecocq F, Ranzani L, Peterson GA, Cicak K, Simmonds RW, Teufel JD, Aumentado J. Nonreciprocal Microwave Signal Processing with a Field-Programmable Josephson Amplifier. Phys Rev Appl 2017; 7:10.1103/physrevapplied.7.024028. [PMID: 38501125 PMCID: PMC10947609 DOI: 10.1103/physrevapplied.7.024028] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
We report on the design and implementation of a field-programmable Josephson amplifier (FPJA)-a compact and lossless superconducting circuit that can be programmed in situ by a set of microwave drives to perform reciprocal and nonreciprocal frequency conversion and amplification. In this work, we demonstrate four modes of operation: frequency conversion (transmission of -0.5 dB, reflection of -30 dB), circulation (transmission of -0.5 dB, reflection of -30 dB, isolation of 30 dB), phase-preserving amplification (gain > 20 dB, one photon of added noise) and directional phase-preserving amplification (reflection of -10 dB, forward gain of 18 dB, reverse isolation of 8 dB, one photon of added noise). The system exhibits quantitative agreement with the theoretical prediction. Based on a gradiometric superconducting quantum-interference device with Nb / Al - AlO x / Nb Josephson junctions, the FPJA is first-order insensitive to flux noise and can be operated without magnetic shielding at low temperature. Owing to its flexible design and compatibility with existing superconducting fabrication techniques, the FPJA offers a straightforward route toward on-chip integration with superconducting quantum circuits such as qubits and microwave optomechanical systems.
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Affiliation(s)
- F. Lecocq
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - L. Ranzani
- Raytheon BBN Technologies, 10 Moulton Street, Cambridge, Massachusetts 02138, USA
| | - G. A. Peterson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - K. Cicak
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - R. W. Simmonds
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J. D. Teufel
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J. Aumentado
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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Allman MS, Whittaker JD, Castellanos-Beltran M, Cicak K, da Silva F, DeFeo MP, Lecocq F, Sirois A, Teufel JD, Aumentado J, Simmonds RW. Tunable resonant and nonresonant interactions between a phase qubit and LC resonator. Phys Rev Lett 2014; 112:123601. [PMID: 24724648 DOI: 10.1103/physrevlett.112.123601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Indexed: 06/03/2023]
Abstract
We use a flux-biased radio frequency superconducting quantum interference device (rf SQUID) with an embedded flux-biased direct current SQUID to generate strong resonant and nonresonant tunable interactions between a phase qubit and a lumped-element resonator. The rf SQUID creates a tunable magnetic susceptibility between the qubit and resonator providing resonant coupling strengths from zero to near the ultrastrong coupling regime. By modulating the magnetic susceptibility, nonresonant parametric coupling achieves rates >100 MHz. Nonlinearity of the magnetic susceptibility also leads to parametric coupling at the subharmonics of the qubit-resonator detuning.
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Affiliation(s)
- M S Allman
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - J D Whittaker
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - M Castellanos-Beltran
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - K Cicak
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - F da Silva
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - M P DeFeo
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - F Lecocq
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - A Sirois
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - J D Teufel
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - J Aumentado
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
| | - R W Simmonds
- National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305-3328, USA
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Teufel JD, Donner T, Li D, Harlow JW, Allman MS, Cicak K, Sirois AJ, Whittaker JD, Lehnert KW, Simmonds RW. Sideband cooling of micromechanical motion to the quantum ground state. Nature 2011; 475:359-63. [DOI: 10.1038/nature10261] [Citation(s) in RCA: 1527] [Impact Index Per Article: 117.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 06/02/2011] [Indexed: 11/09/2022]
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Teufel JD, Li D, Allman MS, Cicak K, Sirois AJ, Whittaker JD, Simmonds RW. Circuit cavity electromechanics in the strong-coupling regime. Nature 2011; 471:204-8. [PMID: 21390127 DOI: 10.1038/nature09898] [Citation(s) in RCA: 622] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 01/31/2011] [Indexed: 11/10/2022]
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Allman MS, Altomare F, Whittaker JD, Cicak K, Li D, Sirois A, Strong J, Teufel JD, Simmonds RW. rf-SQUID-mediated coherent tunable coupling between a superconducting phase qubit and a lumped-element resonator. Phys Rev Lett 2010; 104:177004. [PMID: 20482130 DOI: 10.1103/physrevlett.104.177004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Indexed: 05/29/2023]
Abstract
We demonstrate coherent tunable coupling between a superconducting phase qubit and a lumped-element resonator. The coupling strength is mediated by a flux-biased rf SQUID operated in the nonhysteretic regime. By tuning the applied flux bias to the rf SQUID we change the effective mutual inductance, and thus the coupling energy, between the phase qubit and resonator. We verify the modulation of coupling strength from 0 to 100 MHz by observing modulation in the size of the splitting in the phase qubit's spectroscopy, as well as coherently by observing modulation in the vacuum Rabi oscillation frequency when on resonance. The measured spectroscopic splittings and vacuum Rabi oscillations agree well with theoretical predictions.
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Affiliation(s)
- M S Allman
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305-3328, USA
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Isakovic AF, Evans PG, Kmetko J, Cicak K, Cai Z, Lai B, Thorne RE. Shear modulus and plasticity of a driven charge density wave. Phys Rev Lett 2006; 96:046401. [PMID: 16486854 DOI: 10.1103/physrevlett.96.046401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Indexed: 05/06/2023]
Abstract
We have probed the effects of transverse variations in pinning strength on charge-density-wave (CDW) structure in NbSe3 by x-ray micro-beam diffraction. In ribbonlike crystals having a large longitudinal step in thickness, the CDW first depins on the thick side of the step, causing rotations of the CDW wave vector. By measuring these rotations as a function of position and electric field, the corresponding shear strains are determined, allowing the CDW's shear modulus to be estimated. These results demonstrate the usefulness of x-ray microdiffraction as a tool in studying collective dynamics in electronic crystals.
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Affiliation(s)
- A F Isakovic
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
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10
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Martinis JM, Cooper KB, McDermott R, Steffen M, Ansmann M, Osborn KD, Cicak K, Oh S, Pappas DP, Simmonds RW, Yu CC. Decoherence in Josephson qubits from dielectric loss. Phys Rev Lett 2005; 95:210503. [PMID: 16384123 DOI: 10.1103/physrevlett.95.210503] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Indexed: 05/05/2023]
Abstract
Dielectric loss from two-level states is shown to be a dominant decoherence source in superconducting quantum bits. Depending on the qubit design, dielectric loss from insulating materials or the tunnel junction can lead to short coherence times. We show that a variety of microwave and qubit measurements are well modeled by loss from resonant absorption of two-level defects. Our results demonstrate that this loss can be significantly reduced by using better dielectrics and fabricating junctions of small area . With a redesigned phase qubit employing low-loss dielectrics, the energy relaxation rate has been improved by a factor of 20, opening up the possibility of multiqubit gates and algorithms.
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Affiliation(s)
- John M Martinis
- Department of Physics, University of California, Santa Barbara, California 93106, USA
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McDermott R, Simmonds RW, Steffen M, Cooper KB, Cicak K, Osborn KD, Oh S, Pappas DP, Martinis JM. Simultaneous State Measurement of Coupled Josephson Phase Qubits. Science 2005; 307:1299-302. [PMID: 15731451 DOI: 10.1126/science.1107572] [Citation(s) in RCA: 247] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
One of the many challenges of building a scalable quantum computer is single-shot measurement of all the quantum bits (qubits). We have used simultaneous single-shot measurement of coupled Josephson phase qubits to directly probe interaction of the qubits in the time domain. The concept of measurement crosstalk is introduced, and we show that its effects are minimized by careful adjustment of the timing of the measurements. We observe the antiphase oscillation of the two-qubit 01 and 10 states, consistent with quantum mechanical entanglement of these states, thereby opening the possibility for full characterization of multiqubit gates and elementary quantum algorithms.
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Affiliation(s)
- R McDermott
- Department of Physics, University of California, Santa Barbara, CA 93106, USA
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Abstract
We have explored the shear plasticity of charge density waves (CDWs) in NbSe3 samples with cross sections having a single microfabricated thickness step. Shear stresses along the step result from thickness-dependent CDW pinning. For small thickness differences the CDW depins elastically at the volume average depinning field. For large thickness differences the thicker, more weakly pinned side depins first via plastic shear, and shear plasticity contributes substantial dissipation well above the depinning field. A simple model describes the qualitative features of our data and yields a value for the CDW's shear strength of approximately 9.5 x 10(3) Nm(-2). This value is orders of magnitude smaller than the CDW's longitudinal modulus but much larger than corresponding values for flux line lattices, and in part explains the relative coherence of the CDW response.
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Affiliation(s)
- K O'Neill
- Laboratory of Atomic and Solid State Physics, Clark Hall, Cornell University, Ithaca, New York 14853-2501, USA
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