1
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González-Gutiérrez C, García-Pons D, Zueco D, Martínez-Pérez MJ. Scanning Spin Probe Based on Magnonic Vortex Quantum Cavities. ACS NANO 2024; 18:4717-4725. [PMID: 38271997 PMCID: PMC10867890 DOI: 10.1021/acsnano.3c06704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
Performing nanoscale scanning electron paramagnetic resonance (EPR) requires three essential ingredients: First, a static magnetic field together with field gradients to Zeeman split the electronic energy levels with spatial resolution; second, a radio frequency (rf) magnetic field capable of inducing spin transitions; finally, a sensitive detection method to quantify the energy absorbed by spins. This is usually achieved by combining externally applied magnetic fields with inductive coils or cavities, fluorescent defects, or scanning probes. Here, we theoretically propose the realization of an EPR scanning sensor merging all three characteristics into a single device: the vortex core stabilized in ferromagnetic thin-film discs. On one hand, the vortex ground state generates a significant static magnetic field and field gradients. On the other hand, the precessional motion of the vortex core around its equilibrium position produces a circularly polarized oscillating magnetic field, which is enough to produce spin transitions. Finally, the spin-magnon coupling broadens the vortex gyrotropic frequency, suggesting a direct measure of the presence of unpaired electrons. Moreover, the vortex core can be displaced by simply using external magnetic fields of a few mT, enabling EPR scanning microscopy with large spatial resolution. Our numerical simulations show that, by using low damping magnets, it is theoretically possible to detect single spins located on the disc's surface. Vortex nanocavities could also attain strong coupling to individual spin molecular qubits with potential applications to mediate qubit-qubit interactions or to implement qubit readout protocols.
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Affiliation(s)
- Carlos
A. González-Gutiérrez
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza ES-50009, Spain
- Department
of Physics and Applied Physics, University
of Massachusetts, Lowell, Massachusetts 01854, United States
- Instituto
de Ciencias Físicas, Universidad
Nacional Autónoma de México, Av. Universidad s/n, Cuernavaca, Morelos 62210, México
| | - David García-Pons
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza ES-50009, Spain
| | - David Zueco
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza ES-50009, Spain
| | - María José Martínez-Pérez
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza ES-50009, Spain
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2
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Chiesa A, Santini P, Garlatti E, Luis F, Carretta S. Molecular nanomagnets: a viable path toward quantum information processing? REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:034501. [PMID: 38314645 DOI: 10.1088/1361-6633/ad1f81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 01/17/2024] [Indexed: 02/06/2024]
Abstract
Molecular nanomagnets (MNMs), molecules containing interacting spins, have been a playground for quantum mechanics. They are characterized by many accessible low-energy levels that can be exploited to store and process quantum information. This naturally opens the possibility of using them as qudits, thus enlarging the tools of quantum logic with respect to qubit-based architectures. These additional degrees of freedom recently prompted the proposal for encoding qubits with embedded quantum error correction (QEC) in single molecules. QEC is the holy grail of quantum computing and this qudit approach could circumvent the large overhead of physical qubits typical of standard multi-qubit codes. Another important strength of the molecular approach is the extremely high degree of control achieved in preparing complex supramolecular structures where individual qudits are linked preserving their individual properties and coherence. This is particularly relevant for building quantum simulators, controllable systems able to mimic the dynamics of other quantum objects. The use of MNMs for quantum information processing is a rapidly evolving field which still requires to be fully experimentally explored. The key issues to be settled are related to scaling up the number of qudits/qubits and their individual addressing. Several promising possibilities are being intensively explored, ranging from the use of single-molecule transistors or superconducting devices to optical readout techniques. Moreover, new tools from chemistry could be also at hand, like the chiral-induced spin selectivity. In this paper, we will review the present status of this interdisciplinary research field, discuss the open challenges and envisioned solution paths which could finally unleash the very large potential of molecular spins for quantum technologies.
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Affiliation(s)
- A Chiesa
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
| | - P Santini
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
| | - E Garlatti
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
| | - F Luis
- Instituto de Nanociencia y Materiales de Aragon (INMA), CSIC, Universidad de Zaragoza, Zaragoza, Spain
- Departamento de Fısica de la Materia Condensada, Universidad de Zaragoza, Zaragoza, Spain
| | - S Carretta
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
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3
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Tejedor I, Urtizberea A, Natividad E, Martínez JI, Gascón I, Roubeau O. Dilute Gd hydroxycarbonate particles for localized spin qubit integration. MATERIALS HORIZONS 2023; 10:5214-5222. [PMID: 37725390 DOI: 10.1039/d3mh01201h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Molecular spins are considered as the quantum hardware to build hybrid quantum processors in which coupling to superconducting devices would provide the means to implement the necessary coherent manipulations. As an alternative to large magnetically-dilute crystals or concentrated nano-scale deposits of paramagnetic molecules that have been studied so far, the use of pre-formed sub-micronic spherical particles of a doped Gd@Y hydroxycarbonate is evaluated here. Particles with an adjustable number of spin carriers are prepared through the control of both particle size and doping. Bulk magnetic properties and continuous wave and time-domain-EPR spectroscopy show that the Gd spins in these particles are potential qubits with robust quantum coherence. Monolayers of densely-packed particles are then formed interfacially and transferred successfully to the surface of Nb superconducting resonators. Alternatively, these particles are disposed at controlled localizations as isolated groups of a few particles through Dip-Pen Nanolithography using colloidal organic dispersions as ink. Altogether, this study offers new material and methodologies relevant to the development of viable hybrid quantum processors.
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Affiliation(s)
- Inés Tejedor
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain
| | - Ainhoa Urtizberea
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Campus Río Ebro, María de Luna 3, 50018 Zaragoza, Spain.
| | - Eva Natividad
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Campus Río Ebro, María de Luna 3, 50018 Zaragoza, Spain.
| | - Jesús I Martínez
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain
| | - Ignacio Gascón
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain
| | - Olivier Roubeau
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain
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4
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Winkler R, Ciria M, Ahmad M, Plank H, Marcuello C. A Review of the Current State of Magnetic Force Microscopy to Unravel the Magnetic Properties of Nanomaterials Applied in Biological Systems and Future Directions for Quantum Technologies. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2585. [PMID: 37764614 PMCID: PMC10536909 DOI: 10.3390/nano13182585] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
Magnetism plays a pivotal role in many biological systems. However, the intensity of the magnetic forces exerted between magnetic bodies is usually low, which demands the development of ultra-sensitivity tools for proper sensing. In this framework, magnetic force microscopy (MFM) offers excellent lateral resolution and the possibility of conducting single-molecule studies like other single-probe microscopy (SPM) techniques. This comprehensive review attempts to describe the paramount importance of magnetic forces for biological applications by highlighting MFM's main advantages but also intrinsic limitations. While the working principles are described in depth, the article also focuses on novel micro- and nanofabrication procedures for MFM tips, which enhance the magnetic response signal of tested biomaterials compared to commercial nanoprobes. This work also depicts some relevant examples where MFM can quantitatively assess the magnetic performance of nanomaterials involved in biological systems, including magnetotactic bacteria, cryptochrome flavoproteins, and magnetic nanoparticles that can interact with animal tissues. Additionally, the most promising perspectives in this field are highlighted to make the reader aware of upcoming challenges when aiming toward quantum technologies.
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Affiliation(s)
- Robert Winkler
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria; (R.W.); (H.P.)
| | - Miguel Ciria
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain;
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Margaret Ahmad
- Photobiology Research Group, IBPS, UMR8256 CNRS, Sorbonne Université, 75005 Paris, France;
| | - Harald Plank
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria; (R.W.); (H.P.)
- Graz Centre for Electron Microscopy, 8010 Graz, Austria
- Institute of Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
| | - Carlos Marcuello
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain;
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
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5
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Wang Y, Dou W. Nonadiabatic dynamics near metal surfaces under Floquet engineering: Floquet electronic friction vs Floquet surface hopping. J Chem Phys 2023; 159:094103. [PMID: 37655774 DOI: 10.1063/5.0161292] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/10/2023] [Indexed: 09/02/2023] Open
Abstract
In the previous study Wang and Dou [J. Chem. Phys. 158, 224109 (2023)], we have derived a Floquet classical master equation (FCME) to treat nonadiabatic dynamics near metal surfaces under Floquet engineering. We have also proposed a trajectory surface hopping algorithm to solve the FCME. In this study, we map the FCME into a Floquet Fokker-Planck equation in the limit of fast Floquet driving and fast electron motion as compared to nuclear motion. The Fokker-Planck equation is then being solved using Langevin dynamics with explicit friction and random force from the nonadiabatic effects of hybridized electrons and Floquet states. We benchmark the Floquet electronic friction dynamics against Floquet quantum master equation and Floquet surface hopping. We find that Floquet driving results in a violation of the second fluctuation-dissipation theorem, which further gives rise to heating effects.
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Affiliation(s)
- Yu Wang
- Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, Zhejiang, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Wenjie Dou
- Department of Chemistry, School of Science, Westlake University, Hangzhou 310024, Zhejiang, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
- Department of Physics, School of Science, Westlake University, Hangzhou 310024, Zhejiang, China
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6
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Zollitsch CW, Khan S, Nam VTT, Verzhbitskiy IA, Sagkovits D, O'Sullivan J, Kennedy OW, Strungaru M, Santos EJG, Morton JJL, Eda G, Kurebayashi H. Probing spin dynamics of ultra-thin van der Waals magnets via photon-magnon coupling. Nat Commun 2023; 14:2619. [PMID: 37147370 PMCID: PMC10163026 DOI: 10.1038/s41467-023-38322-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
Layered van der Waals (vdW) magnets can maintain a magnetic order even down to the single-layer regime and hold promise for integrated spintronic devices. While the magnetic ground state of vdW magnets was extensively studied, key parameters of spin dynamics, like the Gilbert damping, crucial for designing ultra-fast spintronic devices, remains largely unexplored. Despite recent studies by optical excitation and detection, achieving spin wave control with microwaves is highly desirable, as modern integrated information technologies predominantly are operated with these. The intrinsically small numbers of spins, however, poses a major challenge to this. Here, we present a hybrid approach to detect spin dynamics mediated by photon-magnon coupling between high-Q superconducting resonators and ultra-thin flakes of Cr2Ge2Te6 (CGT) as thin as 11 nm. We test and benchmark our technique with 23 individual CGT flakes and extract an upper limit for the Gilbert damping parameter. These results are crucial in designing on-chip integrated circuits using vdW magnets and offer prospects for probing spin dynamics of monolayer vdW magnets.
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Affiliation(s)
- Christoph W Zollitsch
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK.
| | - Safe Khan
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK
| | - Vu Thanh Trung Nam
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Ivan A Verzhbitskiy
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Dimitrios Sagkovits
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - James O'Sullivan
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK
| | - Oscar W Kennedy
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK
| | - Mara Strungaru
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
| | - Elton J G Santos
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
- Higgs Centre for Theoretical Physics, The University of Edinburgh, Edinburgh, EH9 3FD, UK
| | - John J L Morton
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK
- Department of Electronic & Electrical Engineering, UCL, London, WC1E 7JE, UK
| | - Goki Eda
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
- Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Hidekazu Kurebayashi
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WCH1 0AH, UK
- Department of Electronic & Electrical Engineering, UCL, London, WC1E 7JE, UK
- WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Sendai, 980- 8577, Japan
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7
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Tesi L, Stemmler F, Winkler M, Liu SSY, Das S, Sun X, Zharnikov M, Ludwigs S, van Slageren J. Modular Approach to Creating Functionalized Surface Arrays of Molecular Qubits. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208998. [PMID: 36609776 DOI: 10.1002/adma.202208998] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/30/2022] [Indexed: 06/17/2023]
Abstract
The quest for developing quantum technologies is driven by the promise of exponentially faster computations, ultrahigh performance sensing, and achieving thorough understanding of many-particle quantum systems. Molecular spins are excellent qubit candidates because they feature long coherence times, are widely tunable through chemical synthesis, and can be interfaced with other quantum platforms such as superconducting qubits. A present challenge for molecular spin qubits is their integration in quantum devices, which requires arranging them in thin films or monolayers on surfaces. However, clear proof of the survival of quantum properties of molecular qubits on surfaces has not been reported so far. Furthermore, little is known about the change in spin dynamics of molecular qubits going from the bulk to monolayers. Here, a versatile bottom-up method is reported to arrange molecular qubits as functional groups of self-assembled monolayers (SAMs) on surfaces, combining molecular self-organization and click chemistry. Coherence times of up to 13 µs demonstrate that qubit properties are maintained or even enhanced in the monolayer.
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Affiliation(s)
- Lorenzo Tesi
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Friedrich Stemmler
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Mario Winkler
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Sherri S Y Liu
- IPOC-Functional Polymers, Institute of Polymer Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Saunak Das
- Applied Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Xiuming Sun
- IPOC-Functional Polymers, Institute of Polymer Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Michael Zharnikov
- Applied Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Sabine Ludwigs
- IPOC-Functional Polymers, Institute of Polymer Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Joris van Slageren
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
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8
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Lockyer SJ, Chiesa A, Brookfield A, Timco GA, Whitehead GFS, McInnes EJL, Carretta S, Winpenny REP. Five-Spin Supramolecule for Simulating Quantum Decoherence of Bell States. J Am Chem Soc 2022; 144:16086-16092. [PMID: 36007954 PMCID: PMC9460766 DOI: 10.1021/jacs.2c06384] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
We report a supramolecule that contains five spins of
two different
types and with, crucially, two different and predictable interaction
energies between the spins. The supramolecule is characterized, and
the interaction energies are demonstrated by electron paramagnetic
resonance (EPR) spectroscopy. Based on the measured parameters, we
propose experiments that would allow this designed supramolecule to
be used to simulate quantum decoherence in maximally entangled Bell
states that could be used in quantum teleportation.
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Affiliation(s)
- Selena J Lockyer
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Alessandro Chiesa
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy.,INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, I-43124 Parma, Italy.,UdR Parma, INSTM, I-43124 Parma, Italy
| | - Adam Brookfield
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Grigore A Timco
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - George F S Whitehead
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Eric J L McInnes
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Stefano Carretta
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy.,INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, I-43124 Parma, Italy.,UdR Parma, INSTM, I-43124 Parma, Italy
| | - Richard E P Winpenny
- Department of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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9
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Magnetic molecules as local sensors of topological hysteresis of superconductors. Nat Commun 2022; 13:3838. [PMID: 35788608 PMCID: PMC9253336 DOI: 10.1038/s41467-022-31320-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 06/14/2022] [Indexed: 11/08/2022] Open
Abstract
Superconductors and magnetic materials, including molecules, are key ingredients for quantum computing and spintronics. However, only a little is known about how these materials interact in multilayer nanostructures like the hybrid architectures nowadays under development for such advanced applications. Here, we show that a single layer of magnetic molecules, Terbium(III) bis-phthalocyaninato (TbPc2) complexes, deposited under controlled UHV conditions on a superconducting Pb(111) surface is sensitive to the topology of the intermediate state of the superconductor, namely to the presence and evolution of superconducting and normal domains due to screening and penetration of an external magnetic field. The topological hysteresis of the superconducting substrate imprints a local evolution of the magnetisation of the TbPc2 molecules in the monolayer. Element and surface selective detection is achieved by recording the X-ray magnetic circular dichroism of the Tb atoms. This study reveals the impressive potential of magnetic molecules for sensing local magnetic field variations in molecular/superconductor hybrid devices, including spin resonators or spin injecting and spin filtering components for spintronics applications.
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10
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Román-Roche J, Luis F, Zueco D. Photon Condensation and Enhanced Magnetism in Cavity QED. PHYSICAL REVIEW LETTERS 2021; 127:167201. [PMID: 34723605 DOI: 10.1103/physrevlett.127.167201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
A system of magnetic molecules coupled to microwave cavities (LC resonators) undergoes the equilibrium superradiant phase transition. The transition is experimentally observable. The effect of the coupling is first illustrated by the vacuum-induced ferromagnetic order in a quantum Ising model and then by the modification of the magnetic phase diagram of Fe_{8} dipolar crystals, exemplifying the cooperation between intrinsic and photon-induced spin-spin interactions. Finally, a transmission experiment is shown to resolve the transition, measuring the quantum electrodynamical control of magnetism.
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Affiliation(s)
- Juan Román-Roche
- Instituto de Nanociencia y Materiales de Aragón (INMA) and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain
| | - Fernando Luis
- Instituto de Nanociencia y Materiales de Aragón (INMA) and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain
| | - David Zueco
- Instituto de Nanociencia y Materiales de Aragón (INMA) and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain
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11
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Lenz S, König D, Hunger D, van Slageren J. Room-Temperature Quantum Memories Based on Molecular Electron Spin Ensembles. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101673. [PMID: 34106491 DOI: 10.1002/adma.202101673] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/06/2021] [Indexed: 06/12/2023]
Abstract
Whilst quantum computing has recently taken great leaps ahead, the development of quantum memories has decidedly lagged behind. Quantum memories are essential devices in the quantum technology palette and are needed for intermediate storage of quantum bit states and as quantum repeaters in long-distance quantum communication. Current quantum memories operate at cryogenic, mostly sub-Kelvin temperatures and require extensive and costly peripheral hardware. It is demonstrated that ensembles of weakly coupled molecular spins show long coherence times and can be used to store microwave pulses of arbitrary phase. These studies exploit strong coupling of the spin ensemble to special 3D microwave resonators. Most importantly, these systems operate at room temperature.
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Affiliation(s)
- Samuel Lenz
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Dennis König
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - David Hunger
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Joris van Slageren
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
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12
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Barrier-free reverse-intersystem crossing in organic molecules by strong light-matter coupling. Nat Commun 2021; 12:3255. [PMID: 34059685 PMCID: PMC8167092 DOI: 10.1038/s41467-021-23481-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/30/2021] [Indexed: 11/17/2022] Open
Abstract
Strong light-matter coupling provides the means to challenge the traditional rules of chemistry. In particular, an energy inversion of singlet and triplet excited states would be fundamentally remarkable since it would violate the classical Hund’s rule. An organic chromophore possessing a lower singlet excited state can effectively harvest the dark triplet states, thus enabling 100% internal quantum efficiency in electrically pumped light-emitting diodes and lasers. Here we demonstrate unambiguously an inversion of singlet and triplet excited states of a prototype molecule by strong coupling to an optical cavity. The inversion not only implies that the polaritonic state lies at a lower energy, but also a direct energy pathway between the triplet and polaritonic states is opened. The intrinsic photophysics of reversed-intersystem crossing are thereby completely overturned from an endothermic process to an exothermic one. By doing so, we show that it is possible to break the limit of Hund’s rule and manipulate the energy flow in molecular systems by strong light-matter coupling. Our results will directly promote the development of organic light-emitting diodes based on reversed-intersystem crossing. Moreover, we anticipate that it provides the pathway to the creation of electrically pumped polaritonic lasers in organic systems. Strong coupling of organic materials with optical cavities allows to manipulate the rate of energy transfer between their internal states. Here, the authors show a hybrid state of singlet character with energy lower than the triplet state, and a flow of energy from the triplet to the hybrid state.
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Gimeno I, Urtizberea A, Román-Roche J, Zueco D, Camón A, Alonso PJ, Roubeau O, Luis F. Broad-band spectroscopy of a vanadyl porphyrin: a model electronuclear spin qudit. Chem Sci 2021; 12:5621-5630. [PMID: 34168797 PMCID: PMC8179683 DOI: 10.1039/d1sc00564b] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/09/2021] [Indexed: 01/08/2023] Open
Abstract
We explore how to encode more than a qubit in vanadyl porphyrin molecules hosting a S = 1/2 electronic spin coupled to a I = 7/2 nuclear spin. The spin Hamiltonian and its parameters, as well as the spin dynamics, have been determined via a combination of electron paramagnetic resonance, heat capacity, magnetization and on-chip magnetic spectroscopy experiments performed on single crystals. We find low temperature spin coherence times of micro-seconds and spin relaxation times longer than a second. For sufficiently strong magnetic fields (B > 0.1 T, corresponding to resonance frequencies of 9-10 GHz) these properties make vanadyl porphyrin molecules suitable qubit realizations. The presence of multiple equispaced nuclear spin levels then merely provides 8 alternatives to define the '1' and '0' basis states. For lower magnetic fields (B < 0.1 T), and lower frequencies (<2 GHz), we find spectroscopic signatures of a sizeable electronuclear entanglement. This effect generates a larger set of allowed transitions between different electronuclear spin states and removes their degeneracies. Under these conditions, we show that each molecule fulfills the conditions to act as a universal 4-qubit processor or, equivalently, as a d = 16 qudit. These findings widen the catalogue of chemically designed systems able to implement non-trivial quantum functionalities, such as quantum simulations and, especially, quantum error correction at the molecular level.
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Affiliation(s)
- Ignacio Gimeno
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
| | - Ainhoa Urtizberea
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
- Centro Universitario de la Defensa 50090 Zaragoza Spain
| | - Juan Román-Roche
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
| | - David Zueco
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
| | - Agustín Camón
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
| | - Pablo J Alonso
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
| | - Olivier Roubeau
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
| | - Fernando Luis
- Instituto de Nanociencia y Materiales de Aragón, CSIC and Universidad de Zaragoza 50009 Zaragoza Spain
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A dissymmetric [Gd 2] coordination molecular dimer hosting six addressable spin qubits. Commun Chem 2020; 3:176. [PMID: 36703386 PMCID: PMC9814487 DOI: 10.1038/s42004-020-00422-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/19/2020] [Indexed: 01/29/2023] Open
Abstract
Artificial magnetic molecules can host several spin qubits, which could then implement small-scale algorithms. In order to become of practical use, such molecular spin processors need to increase the available computational space and warrant universal operations. Here, we design, synthesize and fully characterize dissymetric molecular dimers hosting either one or two Gadolinium(III) ions. The strong sensitivity of Gadolinium magnetic anisotropy to its local coordination gives rise to different zero-field splittings at each metal site. As a result, the [LaGd] and [GdLu] complexes provide realizations of distinct spin qudits with eight unequally spaced levels. In the [Gd2] dimer, these properties are combined with a Gd-Gd magnetic interaction, sufficiently strong to lift all level degeneracies, yet sufficiently weak to keep all levels within an experimentally accessible energy window. The spin Hamiltonian of this dimer allows a complete set of operations to act as a 64-dimensional all-electron spin qudit, or, equivalently, as six addressable qubits. Electron paramagnetic resonance experiments show that resonant transitions between different spin states can be coherently controlled, with coherence times TM of the order of 1 µs limited by hyperfine interactions. Coordination complexes with embedded quantum functionalities are promising building blocks for quantum computation and simulation hybrid platforms.
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Lenz S, Hunger D, van Slageren J. Strong coupling between resonators and spin ensembles in the presence of exchange couplings. Chem Commun (Camb) 2020; 56:12837-12840. [DOI: 10.1039/d0cc04841k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exchange–dependent strong coupling between DPPH radical spins and 3D microwave cavity coupling up to room temperature.
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Affiliation(s)
- Samuel Lenz
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology IQST
- University of Stuttgart
- Stuttgart 70569
- Germany
| | - David Hunger
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology IQST
- University of Stuttgart
- Stuttgart 70569
- Germany
| | - Joris van Slageren
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology IQST
- University of Stuttgart
- Stuttgart 70569
- Germany
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