Dephasing Rate in Dielectric Glasses at Ultralow Temperatures

Burin, Alexander L.; Kagan, Yu.; Maksimov, L. A.; Polishchuk, I. Ya.

doi:10.1103/physrevlett.80.2945

Cited by 52 publications

(59 citation statements)

References 13 publications

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“…In one dimensional quantum systems with shortrange interactions it is now clear that MBL is stable against such thermal inclusions at strong enough randomness [63]. The situation in higher dimensional systems, or one-dimensional systems with longer-range interactions [97,98], is not clear at present, as we shall see.…”

Section: Griffiths Effects In the Mbl Phasementioning

confidence: 85%

Rare‐region effects and dynamics near the many‐body localization transition

et al. 2017

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The low-frequency response of systems near the many-body localization phase transition, on either side of the transition, is dominated by contributions from rare regions that are locally "in the other phase", i.e., rare localized regions in a system that is typically thermal, or rare thermal regions in a system that is typically localized. Rare localized regions affect the properties of the thermal phase, especially in one dimension, by acting as bottlenecks for transport and the growth of entanglement, whereas rare thermal regions in the localized phase act as local "baths" and dominate the low-frequency response of the MBL phase. We review recent progress in understanding these rare-region effects, and discuss some of the open questions associated with them: in particular, whether and in what circumstances a single rare thermal region can destabilize the many-body localized phase.

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Section: Griffiths Effects In the Mbl Phasementioning

confidence: 85%

Rare‐region effects and dynamics near the many‐body localization transition

et al. 2017

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“…To examine the validity of the self-consistent approximation one can make one or more iterative steps expanding the offdiagonal Green functions G a k a in the same manner as it was done in Eq. (43). As shown below these iterations lead to the forward approximation.…”

Section: Localization In the Bethe Lattice With Correlated Site Energmentioning

confidence: 99%

“…The delocalization is associated with the flip-flop terms σ interaction there are flip-flop transitions characterized by an energy change equal to a two spin flip energy difference, which can be made arbitrarily small [42,43].…”

Section: Weak Interactionmentioning

confidence: 99%

Localization and chaos in a quantum spin glass model in random longitudinal fields: Mapping to the localization problem in a Bethe lattice with a correlated disorder

Burin

2017

Annalen der Physik

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The analytical solution of a many-body localization problem in a quantum Sherrington-Kirkpatrick spin glass model in a random longitudinal field is proposed matching the problem with a model of Anderson localization in a Bethe lattice. The localization transition is dramatically sensitive to the relationship between interspin interaction and random field revealing different regimes in which the interaction can either suppress or enhance the delocalization. The localization is enhanced by decreasing the temperature and the localization transition shows a remarkable universality in a spin glass phase. The observed trends should be qualitatively relevant for other systems showing many-body localization.

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“…This corresponds to J/h 1, implying W ≈ J and ξ ≈ (J/h) 2 . However, as was pointed out recently [38], all these studies neglected the phenomenon of spectral diffusion [39,40], which significantly reduces the critical interaction strength in the weak disorder limit to U * ∝ δ ξ (δ ξ /W) α with a positive exponent α = O(1) (up to logarithmic corrections).Discussion and conclusion. We have proposed and analyzed the presumably simplest possible protocol for quantum magnets to exhibit the absence of ergodic dynamics, and thus Many-Body Localization in the form of remanent magnetization in initially ferromagnetically polarized antiferromagnets.…”

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confidence: 97%

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confidence: 99%

Remanent Magnetization: Signature of Many-Body Localization in Quantum Antiferromagnets

Müller

2017

Phys. Rev. Lett.

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We study the remanent magnetization in antiferromagnetic, many-body localized quantum spin chains, initialized in a fully magnetized state. Its long time limit is an order parameter for the localization transition, which is readily accessible by standard experimental probes in magnets. We analytically calculate its value in the strong-disorder regime exploiting the explicit construction of quasi-local conserved quantities of the localized phase. We discuss analogies in cold atomic systems.Introduction. The non-equilibrium dynamics in disordered, isolated quantum systems have been subject to theoretical investigations ever since the notion of localization was introduced in [1]. Spin systems in random fields are prototypical models to analyze the disorderinduced breakdown of thermalization: a large number of studies on disordered spin chains [2][3][4][5][6][7][8][9][10][11][12][13] has provided evidence for a dynamical phase transition between a weakdisorder phase which thermalizes, and a Many-Body Localized (MBL) phase in which excitations do not diffuse, ergodicity is broken and local memory of the initial conditions persists for infinite time [14][15][16].Signatures of MBL are found in the properties of individual many-body eigenstates. Even highly excited eigenstates exhibit area-law scaling of the bipartite entanglement entropy [4,7,8,17] and Poissonian level statistics [2,18,19], both being incompatible with thermalization [20][21][22]. Novel dynamical properties such as the logarithmic spreading of entanglement have been observed in direct simulations of the time evolution [3,23]. The non-equilibrium physics of MBL systems has been probed experimentally in artificial quantum systems made of cold atomic gases [24,25] and trapped ion systems [26], while an indirect signature in the from of strongly suppressed absorption of radiation was found in electron-glasses [27]. However, direct observations of MBL in solid-state materials are still lacking.It has been argued [28][29][30] that the properties of MBL systems are related to the existence of extensively many quasi-local conserved operators that strongly constrain the quantum dynamics, preventing both transport and thermalization. Their existence also follows as a corollary from Imbrie's rigorous arguments in favor of MBL [31,32].In this work, we propose a experimentally readily observable consequence of MBL in quantum magnets: the out-of-equilibrium remanent magnetization that persists after ferromagnetically polarizing an antiferromagnet whose total magnetization is not a conserved. The remanence implies non-ergodicity, since ergodic dynamics would relax the magnetization completely (cf. Fig. 1 for a schematic sketch of the protocol). As an example, we consider an antiferromagnetic, anisotropic Heisenberg spin-1/2 chain(1) subject to random fields h k along the Ising axis. We assume J z < 0, as well as J x = J y to ensure the nonconservation of the total magnetization. Such Hamiltonians can be realized, e.g., in Ising compounds with both exchange and dipola...

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Dephasing Rate in Dielectric Glasses at Ultralow Temperatures

Cited by 52 publications

References 13 publications

Rare‐region effects and dynamics near the many‐body localization transition

Rare‐region effects and dynamics near the many‐body localization transition

Localization and chaos in a quantum spin glass model in random longitudinal fields: Mapping to the localization problem in a Bethe lattice with a correlated disorder

Remanent Magnetization: Signature of Many-Body Localization in Quantum Antiferromagnets

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