Magnonic Superradiant Phase Transition

Bamba, Motoaki; Li, Xinwei; Peraca, Nicolas Marquez; Kono, Junichiro

doi:10.48550/arxiv.2007.13263

Cited by 4 publications

(4 citation statements)

References 66 publications

(176 reference statements)

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“…For instance, Dicke cooperativity was experimentally realized in [29] with spin-magnon interactions in the USC regime. Moreover, recent terahertz magnetospectroscopy experiments [6,26,52] suggest that the magnonic version of the SPT is within reach [53].…”

Section: Discussionmentioning

confidence: 99%

Spectroscopy and critical quantum thermometry in the ultrastrong coupling regime

Salado-Mejía,

Román-Ancheyta,

Soto-Eguibar

et al. 2020

Preprint

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We present an exact analytical solution of the anisotropic Hopfield model, and we use it to investigate in detail the spectral and thermometric response of two ultrastrongly coupled quantum systems. Interestingly, we show that depending on the initial state of the coupled system, the vacuum Rabi splitting manifests significant asymmetries that may be considered spectral signatures of the counterintuitive decoupling effect.Using the coupled system as a thermometer for quantum thermodynamics applications, we obtain the ultimate bounds on the estimation of temperature that remain valid in the ultrastrong coupling regime. Remarkably, if the system performs a quantum phase transition, the quantum Fisher information exhibits periodic divergences, suggesting that one can have several points of arbitrarily high thermometry precision for such a critical quantum sensor.

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Section: Discussionmentioning

confidence: 99%

Spectroscopy and critical quantum thermometry in the ultrastrong coupling regime

Salado-Mejía,

Román-Ancheyta,

Soto-Eguibar

et al. 2020

Preprint

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“…Since the magnets typically interact with the outside world via their spin, the composite and high-spin nature of the squeezed-magnon amplifies its coupling via the squeezing effect [14,152]. This has been clarified in the context of magnon-mediated superconductivity enhancement [227,228] and magnon-magnon ultrastrong coupling [229][230][231], among several others [232][233][234][235]. The nonequilibrium equivalent of this amplification was proposed earlier for squeezed states of light [236][237][238] and has been accomplished recently using ion trap systems [239].…”

Section: Squeezed Statesmentioning

confidence: 96%

Quantum magnonics: when magnon spintronics meets quantum information science

Yuan,

Cao,

Kamra

et al. 2021

Preprint

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Spintronics and quantum information science are two promising candidates for innovating information processing technologies. The combination of these two fields enables us to build solid-state platforms for studying quantum phenomena and for realizing multi-functional quantum tasks. For a long time, however, the intersection of these two fields was limited due to the distinct properties of the classical magnetization, that is manipulated in spintronics, and quantum bits, that are utilized in quantum information science. This situation has changed significantly over the last few years because of the remarkable progress in coding and processing information using magnons. On the other hand, significant advances in understanding the entanglement of quasi-particles and in designing high-quality qubits and photonic cavities for quantum information processing provide physical platforms to integrate magnons with quantum systems. From these endeavours, the highly interdisciplinary field of quantum magnonics emerges, which combines spintronics, quantum optics and quantum information science. Here, we give an overview of the recent developments concerning the quantum states of magnons and their hybridization with mature quantum platforms. First, we review the basic concepts of magnons and quantum entanglement and discuss the generation and manipulation of quantum states of magnons, such as single-magnon states, squeezed states and quantum many-body states including Bose-Einstein condensation and the resulting spin superfluidity. We discuss how magnonic systems can be integrated and entangled with quantum platforms including cavity photons, superconducting qubits, nitrogen-vacancy centers, and phonons for coherent information transfer and collaborative information processing. The implications of these hybrid quantum systems for non-Hermitian physics and parity-time symmetry are highlighted, together with applications in quantum memories and high-precision measurements. Finally, we present an outlook on some of the challenges and opportunities in quantum magnonics.

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“…There is now extensive literature on this topic including extended Dicke models [100][101][102][103][104], connections with quantum chaos [105][106][107], driven and open systems [108][109][110][111][112], and artificial systems [11,[113][114][115][116][117][118][119][120][121][122][123]. The topic has received renewed interest in light of rapid progress in magnonic systems and in controlling correlated electron systems inside cavities [124][125][126][127][128][129].…”

Section: Ground State Superradiancementioning

confidence: 99%

Implications of gauge freedom for nonrelativistic quantum electrodynamics

Stokes¹,

Nazir²

2020

Preprint

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We review gauge-freedom in quantum electrodynamics (QED) outside of textbook regimes. We emphasise that QED subsystems are defined relative to a choice of gauge. Each definition uses different gauge-invariant observables. We show that this relativity is only eliminated if a sufficient number of Markovian and weak-coupling approximations are employed. All physical predictions are gauge-invariant, including subsystem properties such as photon number and entanglement. However, subsystem properties naturally differ for different physical subsystems. Gauge-ambiguities arise not because it is unclear how to obtain gauge-invariant predictions, but because it is not always clear which physical observables are the most operationally relevant. The gauge-invariance of a prediction is necessary but not sufficient to ensure its operational relevance. We show that in controlling which gauge-invariant observables are used to define a material system, the choice of gauge affects the balance between the material system's localisation and its electromagnetic dressing. We review various implications of subsystem gauge-relativity for deriving effective models, for describing timedependent interactions, for photodetection theory, and for describing matter within a cavity.

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Magnonic Superradiant Phase Transition

Cited by 4 publications

References 66 publications

Spectroscopy and critical quantum thermometry in the ultrastrong coupling regime

Spectroscopy and critical quantum thermometry in the ultrastrong coupling regime

Quantum magnonics: when magnon spintronics meets quantum information science

Implications of gauge freedom for nonrelativistic quantum electrodynamics

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