Dynamics of coherence: Maximal quantum Fisher information versus Loschmidt echo

Cheraghi, Hadi; Mahdavifar, S.

doi:10.1103/physrevb.102.024304

Cited by 14 publications

(13 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Specifically, the revival times do not depend on the initial state or the size of the quench and are given by integer multiples of the revival period T rev ≃ N/2v max , with N the system size and v max the maximal group velocity of quasiparticles excited by the quench. This mirrors known results for revival times for the Loschmidt echo [63,64] and maximal quantum Fisher information [61] for quenched quantum many-body systems.…”

Section: Introductionsupporting

confidence: 86%

“…For related results, see Refs. [60,61,79]. Note, however, that in the present case a nonanalyticity appears only when the ground state of the post-quench Hamiltonian itself is critical.…”

Section: A Squeezed Initial Statementioning

confidence: 60%

“…Because of the nonlocal nature of the Jordan-Wigner transformation, this calculation is quite nontrivial. Fortunately, we can rely on well-known results which allow us to express G αα n (t) for n ≥ 1 in terms of Toeplitz determinants [67,73], where [61] G…”

Section: Dynamics Of Spin Squeezingmentioning

confidence: 99%

“…We argue that they occur because of a sudden change in the direction of the local observable which detects the squeezing parameter. We call this phenomenon dynamical spinsqueezing transition, occurring at certain critical times t c and representing a special type of nonequilibrium quantum phase transition [59][60][61] in this class of systems. In addition, we pinpoint a nonanalyticity in the long-time average ξ 2 s (h) of the spin-squeezing parameter (with the quenched transverse field as control parameter), right at the equilibrium quantum critical point h = h c .…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Achieving spin-squeezed states by quench dynamics in a quantum chain

Cheraghi,

Mahdavifar,

Johannesson

2021

Preprint

Self Cite

View full text Add to dashboard Cite

We study the time evolution of spin squeezing in the one-dimensional spin-1/2 XY model with a transverse magnetic field subject to a sudden quantum quench. The initial state is selected from the ground state phase diagram of the model, consisting of ferro-and paramagnetic phases separated by a critical value of the transverse field. Our analysis, based on exact results for the model, reveals that by a proper choice of protocol, a quantum quench from an unsqueezed state can create spin squeezed nonequilibrium states. Moreover, we identify two types of nonanalyticities in the parameter which measures the amount of spin squeezing in the system: one in its time-dependence, the other in its long-time average with the transverse field as control parameter. We argue that the first type of nonanalyticity signals an unconventional nonequilibrium quantum phase transition, appearing at certain critical times when the direction of spin squeezing suddenly changes.

show abstract

Section: Introductionsupporting

confidence: 86%

“…For related results, see Refs. [60,61,79]. Note, however, that in the present case a nonanalyticity appears only when the ground state of the post-quench Hamiltonian itself is critical.…”

Section: A Squeezed Initial Statementioning

confidence: 60%

Section: Dynamics Of Spin Squeezingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Achieving spin-squeezed states by quench dynamics in a quantum chain

Cheraghi,

Mahdavifar,

Johannesson

2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…From theoretical point of view, DQPT has studied the various aspects of integrable and nonintegrable systems. [ 40–45 ] It is predicted that DQPT can be precisely identified by the discontinuities of the Pancharatnam geometric phase during the time evolution. [ 46 ] Moreover, it is demonstrated that nonequilibrium quantum phase transitions can be recognized by nonanalyticities in the long‐time average of the LE [ 47 ] and out‐of‐time‐ordered correlators.…”

Section: Introductionmentioning

confidence: 99%

Dynamical Quantum Phase Transitions in the 1D Nonintegrable Spin‐1/2 Transverse Field XZZ Model

Cheraghi

Mahdavifar

2021

Annalen der Physik

Self Cite

View full text Add to dashboard Cite

Using the Jordan–Wigner mean‐field (JW‐MF) approach, the dynamical quantum phase transition (DQPT) in the 1D spin‐1/2 XZZ model is studied, where the presence of the transverse magnetic field breaks the U(1) symmetry of the Hamiltonian and leads to loss of integrability. In the time evolution of the rate function, three kinds of behaviors will emerge: regular and irregular nonanalytic, and also regular analytic. Examples are given where the rate function shows the regular analytic can appear albeit a quench is crossed from a quantum critical point (QCP) and examples where the irregular nonanalyticity behaviors can arise in both quenching into the same phase and exceeded from a QCP. All the regular nonanalyticity behaviors at periodic instants t∗ happen when quenches cross from a QCP. In order to achieve a confirmation on our results, the long‐time average of the rate function is determined and show the occurrence of the nonequilibrium quantum phase transitions exactly at the QCPs and hence disclose the JW‐MF approach qualitatively works very well.

show abstract

Thermodynamic cost of quantum transfers

Ahadpour

Мирмасоуди

2022

Appl. Phys. B

View full text Add to dashboard Cite

In this work, we will study thermodynamic cost of dense coding. In this regard, a scheme is proposed for quantum channel where is induced from two initially uncorrelated thermal quantum systems. At first, the quantum Fisher information and spin squeezing is used to quantify the correlation dynamics over the system. The system reveals that the dynamics of quantum correlations depends crucially on specific energy and temperature. Also, they can be utilized as control parameters for optimal dense coding. Several interesting features of the variations of the energy cost and the dense coding capacity are obtained. It can keep its own valid capacity value in a broad range of temperature by increasing in the energy value of excited states. Also, we can identify valid dense coding with the help of calculating energy cost in the system. Using this approach, identifying a critical point of this model in dense coding capacity quality can be very effective.

show abstract

Dynamics of coherence: Maximal quantum Fisher information versus Loschmidt echo

Cited by 14 publications

References 72 publications

Achieving spin-squeezed states by quench dynamics in a quantum chain

Achieving spin-squeezed states by quench dynamics in a quantum chain

Dynamical Quantum Phase Transitions in the 1D Nonintegrable Spin‐1/2 Transverse Field XZZ Model

Thermodynamic cost of quantum transfers

Contact Info

Product

Resources

About