Decoherence from spin environment: Role of the Dzyaloshinsky-Moriya interaction

Cheng, Wei‐Wen; Liu, J.-M.

doi:10.1103/physreva.79.052320

Cited by 52 publications

(38 citation statements)

References 40 publications

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“…In previous studies, all the spins of the lattice were coupled to the TLS (M is set to N ) with uniform coupling strength [37][38][39][40][41][42][43] or site-dependent coupling strength. 45 The latter reflects the actual coupling strength of the TLSlattice interactions that depend on the location of the TLS in the spin lattice.…”

Section: Spin-lattice Subenvironmentmentioning

confidence: 99%

“…31 Moreover, molecular magnet systems 32,33 and Josephson junction systems 34,35 are described by this model. In the past, various forms of a 1D spin lattice, such as the Ising, 36,37 XY , [38][39][40][41][42] and XXZ [43][44][45] models, have been investigated. Such spin-lattice systems, when isolated, exhibit quantum phase transitions depending on the system parameters.…”

Section: Introductionmentioning

confidence: 99%

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Open quantum dynamics theory for a complex subenvironment system with a quantum thermostat: Application to a spin heat bath

Nakamura,

Tanimura

2021

Preprint

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Complex environments, such as molecular matrices and biological material, play a fundamental role in many important dynamic processes in condensed phases. Because it is extremely difficult to conduct full quantum dynamics simulations on such environments due to their many degrees of freedom, here we treat in detail the environment only around the main system of interest (the subenvironment), while the other degrees of freedom needed to maintain the equilibrium temperature are described by a simple harmonic bath, which we call a quantum thermostat. The noise generated by the subenvironment is spatially non-local and non-Gaussian and cannot be characterized by the fluctuation-dissipation theorem. We describe this model by simulating the dynamics of a two-level system (TLS) that interacts with a subenvironment consisting of a one-dimensional XXZ spin chain. The hierarchical Schrödinger equations of motion are employed to describe the quantum thermostat, allowing time-irreversible simulations of the dynamics at arbitrary temperature. To see the effects of a quantum phase transition of the subenvironment, we investigate the decoherence and relaxation processes of the TLS at zero and finite temperatures for various values of the spin anisotropy. We observed the decoherence of the TLS at finite temperature, even when the anisotropy of the XXZ model is enormous. We also found that the population relaxation dynamics of the TLS changed in a complex manner with the change of the anisotropy and the ferromagnetic or antiferromagnetic orders of the spins.

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Section: Spin-lattice Subenvironmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Open quantum dynamics theory for a complex subenvironment system with a quantum thermostat: Application to a spin heat bath

Nakamura,

Tanimura

2021

Preprint

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“…with q = A, B summed over. In the same way as above, the effective potential from the qubit can be included by simply replacing h by h + δ in (15). Since H k conserves the number parity (even or odd number of electrons), it is sufficient to consider the even-parity subspace of the Hilbert space, spanned by…”

Section: A Preliminariesmentioning

confidence: 99%

“…To understand the physics behind the different behaviors of the LE at the IP (J e = J o ) and away from the IP (J e = J o ), let us recall that the oscillation amplitudes in (20) are made up of products of state overlaps F m,k = | ψ m,k (δ)|ψ 0,k (0) | 2 (m = 0, ..., 7). Knowing that |ψ m,k (0) is an eigenstate of H k in (15), implying that ψ m,k (0)|ψ 0,k (0) = δ m0 (up to a normalization factor), one may be tempted to argue that ψ m,k (δ)|ψ 0,k (0) must be very small for all m = 0 since δ is a small perturbation. If this were the case, however, all oscillation amplitudes in (20) would be vanishingly small for any k, resulting in a non-decaying LE with a value close to unity.…”

Section: B Loschmidt Echo: Zero Magnetic Fieldmentioning

confidence: 99%

Decoherence from spin environments: Loschmidt echo and quasiparticle excitations

Jafari

Johannesson

2017

Phys. Rev. B

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We revisit the problem of decoherence of a qubit centrally coupled to an interacting spin environment, here modeled by a quantum compass chain or an extended XY model in a staggered magnetic field. These two models both support distinct spin liquid phases, adding a new element to the problem. By analyzing their Loschmidt echoes when perturbed by the qubit we find that a fast decoherence of the qubit is conditioned on the presence of propagating quasiparticles which couple to it. Different from expectations based on earlier works on central spin models, our result implies that the closeness of an environment to a quantum phase transition is neither a sufficient nor a necessary condition for an accelerated decoherence rate of a qubit.

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“…On the other hand, one can identify the quantum phase transition through the quantum-classical transition of the system described by a reduction from a pure state to a mixture 14 . This stimulates a series of works regarding the disentanglement of central spins subjected to critical surrounding environment 10 15 16 17 18 19 20 21 . It was shown that at the critical point where the environment occurs QPT, the decoherence is enhanced, and the disentanglement process is accelerated by the quantum criticality.…”

mentioning

confidence: 99%

Quantum correlation dynamics subjected to critical spin environment with short-range anisotropic interaction

Guo

Zhang

2016

Sci Rep

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Short-range interaction among the spins can not only results in the rich phase diagram but also brings about fascinating phenomenon both in the contexts of quantum computing and information. In this paper, we investigate the quantum correlation of the system coupled to a surrounding environment with short-range anisotropic interaction. It is shown that the decay of quantum correlation of the central spins measured by pairwise entanglement and quantum discord can serve as a signature of quantum phase transition. In addition, we study the decoherence factor of the system when the environment is in the vicinity of the phase transition point. In the strong coupling regime, the decay of the decoherence factor exhibits Gaussian envelop in the time domain. However, in weak coupling limit, the quantum correlation of the system is robust against the disturbance of the magnetic field through optimal control of the anisotropic short-range interaction strength. Based on this, the effects of the short-range anisotropic interaction on the sudden transition from classical to quantum decoherence are also presented.The quantum aspects of correlations in composite systems are a key issue in quantum information theory 1 . Quantum entanglement, which determines the given state is separable or not, has been regarded as a valuable resource for quantum information processing 2 . Even many people take it granted that quantum entanglement is quantum correlation. However, some separate states also contains quantum correlation and there exist quantum tasks that display the quantum advantage without entanglement 3 , so entanglement is not the only type of quantum correlation. Quantum discord (QD) defined as the difference between quantum mutual information and classical correlation 4 , is supposed to characterize all of nonclassical correlations including entanglement. Such states with non-zero QD but not entanglement may be responsible for the efficiency of a quantum computer 5,6 . Consequently, QD is believed a new resource for quantum computation.Meanwhile, study of quantum phase transition (QPT) 7 purely driven by quantum fluctuations can help us understand the physical properties of various matters from the perspective of quantum mechanics. During the past decade, the central spin model served as a paradimatic model characterizing the interaction between the quantum system and surrounding environment has received a lot of attentions [8][9][10] . On the one hand, it can provide a platform to investigate the underlying mechanism of the decoherence 11,12 due to the exact solvability of the model, which can pave the way to develop new methods that enhance the coherence time in the context of quantum computation and information 1,13 . On the other hand, one can identify the quantum phase transition through the quantum-classical transition of the system described by a reduction from a pure state to a mixture 14 . This stimulates a series of works regarding the disentanglement of central spins subjected to critical surrounding environment 10...

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Decoherence from spin environment: Role of the Dzyaloshinsky-Moriya interaction

Cited by 52 publications

References 40 publications

Open quantum dynamics theory for a complex subenvironment system with a quantum thermostat: Application to a spin heat bath

Open quantum dynamics theory for a complex subenvironment system with a quantum thermostat: Application to a spin heat bath

Decoherence from spin environments: Loschmidt echo and quasiparticle excitations

Quantum correlation dynamics subjected to critical spin environment with short-range anisotropic interaction

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