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Silevitch DM, Tang C, Aeppli G, Rosenbaum TF. Tuning high-Q nonlinear dynamics in a disordered quantum magnet. Nat Commun 2019; 10:4001. [PMID: 31488819 PMCID: PMC6728381 DOI: 10.1038/s41467-019-11985-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 08/13/2019] [Indexed: 11/09/2022] Open
Abstract
Quantum states cohere and interfere. Atoms arranged imperfectly in a solid rarely display these properties. Here we demonstrate an exception in a disordered quantum magnet that divides itself into nearly isolated subsystems. We probe these coherent spin clusters by driving the system nonlinearly and measuring the resulting hole in the linear spectral response. The Fano shape of the hole encodes the incoherent lifetime as well as coherent mixing of the localized excitations. For the Ising magnet LiHo0.045Y0.955F4, the quality factor Q for spectral holes can be as high as 100,000. We tune the dynamics by sweeping the Fano mixing parameter q through zero via the ac pump amplitude as well as a dc transverse field. The zero crossing of q is associated with a dissipationless response at the drive frequency. Identifying localized two-level systems in a dense and disordered magnet advances the search for qubit platforms emerging from strongly interacting, many-body systems.
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Affiliation(s)
- D M Silevitch
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California, 91125, USA
| | - C Tang
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California, 91125, USA
| | - G Aeppli
- Department of Physics, ETH Zurich, Zurich, CH-8093, Switzerland
- Department de Physique, EPF Lausanne, Lausanne, CH-1015, Switzerland
- Paul Scherrer Institut, Villigen, PSI, CH-5232, Switzerland
| | - T F Rosenbaum
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California, 91125, USA.
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Cortés-Morales EC, Elizondo-Aguilera LF, Medina-Noyola M. Equilibration and Aging of Liquids of Non-Spherically Interacting Particles. J Phys Chem B 2016; 120:7975-87. [DOI: 10.1021/acs.jpcb.6b04635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ernesto C. Cortés-Morales
- Instituto
de Física Manuel Sandoval Vallarta, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000 San Luis Potosí,
SLP, México
| | - L. F. Elizondo-Aguilera
- Departamento
de Ingeniería Física, División de Ciencias e
Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, México
- Institut für
Materialphysik im Weltraum, Deutsches Zentrum für Luft-und
Raumfahrt (DLR), 51170 Köln, Germany
| | - M. Medina-Noyola
- Instituto
de Física Manuel Sandoval Vallarta, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000 San Luis Potosí,
SLP, México
- Departamento
de Ingeniería Física, División de Ciencias e
Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, México
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Sala G, Gutmann MJ, Prabhakaran D, Pomaranski D, Mitchelitis C, Kycia JB, Porter DG, Castelnovo C, Goff JP. Vacancy defects and monopole dynamics in oxygen-deficient pyrochlores. NATURE MATERIALS 2014; 13:488-493. [PMID: 24728463 DOI: 10.1038/nmat3924] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 02/24/2014] [Indexed: 06/03/2023]
Abstract
The idea of magnetic monopoles in spin ice has enjoyed much success at intermediate temperatures, but at low temperatures a description in terms of monopole dynamics alone is insufficient. Recently, numerical simulations were used to argue that magnetic impurities account for this discrepancy by introducing a magnetic equivalent of residual resistance in the system. Here we propose that oxygen deficiency is the leading cause of magnetic impurities in as-grown samples, and we determine the defect structure and magnetism in Y2Ti2O7-δ using diffuse neutron scattering and magnetization measurements. These defects are eliminated by oxygen annealing. The introduction of oxygen vacancies causes Ti(4+) to transform to magnetic Ti(3+) with quenched orbital magnetism, but the concentration is anomalously low. In the spin-ice material Dy2Ti2O7 we find that the same oxygen-vacancy defects suppress moments on neighbouring rare-earth sites, and that these magnetic distortions markedly slow down the long-time monopole dynamics at sub-Kelvin temperatures.
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Affiliation(s)
- G Sala
- Department of Physics, Royal Holloway, University of London, Egham TW20 0EX, UK
| | - M J Gutmann
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK
| | - D Prabhakaran
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - D Pomaranski
- Department of Physics and Astronomy and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, Ontario N2L3G1, Canada
| | - C Mitchelitis
- Department of Physics and Astronomy and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, Ontario N2L3G1, Canada
| | - J B Kycia
- Department of Physics and Astronomy and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, Ontario N2L3G1, Canada
| | - D G Porter
- Department of Physics, Royal Holloway, University of London, Egham TW20 0EX, UK
| | - C Castelnovo
- Theory of Condensed Matter group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - J P Goff
- Department of Physics, Royal Holloway, University of London, Egham TW20 0EX, UK
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Using thermal boundary conditions to engineer the quantum state of a bulk magnet. Proc Natl Acad Sci U S A 2014; 111:3689-94. [PMID: 24567389 DOI: 10.1073/pnas.1316070111] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The degree of contact between a system and the external environment can alter dramatically its proclivity to quantum mechanical modes of relaxation. We show that controlling the thermal coupling of cubic-centimeter-sized crystals of the Ising magnet LiHo(x)Y(1-x)F4 to a heat bath can be used to tune the system between a glassy state dominated by thermal excitations over energy barriers and a state with the hallmarks of a quantum spin liquid. Application of a magnetic field transverse to the Ising axis introduces both random magnetic fields and quantum fluctuations, which can retard and speed the annealing process, respectively, thereby providing a mechanism for continuous tuning between the destination states. The nonlinear response of the system explicitly demonstrates quantum interference between internal and external relaxation pathways.
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