Robustness of entanglement as an indicator of topological phases in quantum walks

Wang, Qinqin; Xu, Xiao‐Ye; Pan, Weiwei; Tao, Si-Jing; Chen, Zhe; Zhan, Yong-Tao; Sun, Kai; Xu, Jin‐Shi; Chen, Geng; Han, Yong‐Jian; Li, Chuan‐Feng; Guo, Guang‐Can

doi:10.1364/optica.375388

Cited by 13 publications

(5 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dynamical evolution of the whole system is chosen to be governed by an effective Hamiltonian . The spin–orbit coupling results in the mixture of the spin subsystem, whose time-averaged state finally relaxes to a steady state and is in the vicinity of it in most of the time steps, indicating the equilibration of the subsystem 51 , 52 . As depicted in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Supplementary Section A , the long-time-averaged state of the spin subsystem in the QW can always relax to a steady state 51 , 52 : , where I is the 2 × 2 identity matrix, represents the initial probability distribution in momentum space, and n i denotes the initial Bloch vector. Moreover, the steady state can be obtained by tracing out bath from the “diagonal ensemble” 6 or be directly calculated by averaging the long-time dynamics of the spin subsystem 43 (for details, see Supplementary Section A ).…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…As shown in Supplementary Section A, the longtime-averaged state of the spin subsystem in the QW can always relax to a steady state 51,52 :…”

Section: Equilibration Of the Spin Subsystemmentioning

confidence: 99%

See 2 more Smart Citations

Experimental verification of generalized eigenstate thermalization hypothesis in an integrable system

et al. 2022

Self Cite

View full text Add to dashboard Cite

Identifying the general mechanics behind the equilibration of a complex isolated quantum system towards a state described by only a few parameters has been the focus of attention in non-equilibrium thermodynamics. And several experimentally unproven conjectures are proposed for the statistical description of quantum (non-)integrable models. The plausible eigenstate thermalization hypothesis (ETH), which suggests that each energy eigenstate itself is thermal, plays a crucial role in understanding the quantum thermalization in non-integrable systems; it is commonly believed that it does not exist in integrable systems. Nevertheless, integrable systems can still relax to the generalized Gibbs ensemble. From a microscopic perspective, understanding the origin of this generalized thermalization that occurs in an isolated integrable system is a fundamental open question lacking experimental investigations. Herein, we experimentally investigated the spin subsystem relaxation in an isolated spin–orbit coupling quantum system. By applying the quantum state engineering technique, we initialized the system with various distribution widths in the mutual eigenbasis of the conserved quantities. Then, we compared the steady state of the spin subsystem reached in a long-time coherent dynamics to the prediction of a generalized version of ETH and the underlying mechanism of the generalized thermalization is experimentally verified for the first time. Our results facilitate understanding the origin of quantum statistical mechanics.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

Experimental verification of generalized eigenstate thermalization hypothesis in an integrable system

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…Different geometries on which the walker can evolve have been realized, including walks on circles with periodic boundary conditions [25][26][27]. Quantum correlations in various quantum walk scenarios have led to a much deeper understanding of how quantum features can propagate, with entanglement being the most prominent and most useful quantum correlation property [28][29][30][31][32][33]. Other successful applications include studying topological phases [34], measurementinduced coherence effects [35], phase-space-based characterizations [36], the ability to dynamically create and annihilate photons (i.e., walkers) [37], non-localized input states [38], large-scale fiber-assisted quantum walks [39], singleand multi-photon interference [40][41][42], etc.…”

Section: Introductionmentioning

confidence: 99%

Driven Gaussian quantum walks

Held,

Engelkemeier,

et al. 2021

Preprint

View full text Add to dashboard Cite

Quantum walks function as essential means to implement quantum simulators, allowing one to study complex and often directly inaccessible quantum processes in controllable systems. In this contribution, the new notion of a driven Gaussian quantum walk is introduced. In contrast to typically considered quantum walks in optical settings, we describe the operation of the walk in terms of a nonlinear map rather than a unitary operation, e.g., by replacing a beam-splitter-type coin with a two-mode squeezer, being a process that is controlled and driven by a pump field. This opens previously unattainable possibilities for kinds of quantum walks that include nonlinear elements as core components of their operation, vastly extending the range of applications of quantum simulators. A full framework for driven Gaussian quantum walks is developed, including methods to characterize nonlinear, quantum, and quantum-nonlinear effects in measurements. Moreover, driven Gaussian quantum walks are compared with their classically interfering and linear counterparts, which are based on classical coherence of light rather than quantum superpositions of states. In particular, the generation and amplification of highly multimode entanglement, squeezing, and other quantum effects are studied over the duration of the nonlinear walk. Importantly, we prove the quantumness of the dynamics itself, regardless of the input state. Furthermore, nonlinear properties of driven Gaussian quantum walks are explored, such as amplification that leads to an ever increasing number of correlated quantum particles, constituting a source of new walkers during a walk. Therefore, the concept for quantum walks is proposed that leads to directly accessible quantum phenomena and renders the quantum simulation of nonlinear processes possible.

show abstract

“…Instead, incorporating the concept of quantum correlations in detection of this kind of transitions, known as topological QPTs, has been significantly successful according to the recent studies. [3][4][5][6][7][8] Two-site quantum correlations gain DOI: 10.1002/andp.202000384 information on how a considered pair of particles in a many-body system are mutually related, a key point in the formation of systemphase.…”

Section: Introductionmentioning

confidence: 99%

Quantum Critical Lines in the Ground State Phase Diagram of Spin‐1/2 Frustrated Transverse‐Field Ising Chains

2020

View full text Add to dashboard Cite

This paper focuses on the ground state phase diagram of a 1D spin‐1/2 quantum Ising model with competing first and second nearest neighbour interactions known as the axial next nearest neighbour Ising model in the presence of a transverse magnetic field. Here, using quantum correlations, both numerically and analytically, some evidence is provided to clarify the identification of the ground state phase diagram. Local quantum correlations play a crucial role in detecting the critical lines either revealed or hidden by symmetry‐breaking. A non‐symmetry‐breaking disorder transition line can be identified by the first derivative of both entanglement of formation and quantum discord between nearest neighbour spins. In addition, the quantum correlations between the second neighbour spins can also be used to reveal Kosterlitz–Thouless phase transition when their interaction strength grows and becomes closer to the first nearest neighbour one. The results obtained using the Jordan–Wigner transformation confirm the accuracy of the numerical case.

show abstract

Robustness of entanglement as an indicator of topological phases in quantum walks

Cited by 13 publications

References 63 publications

Experimental verification of generalized eigenstate thermalization hypothesis in an integrable system

Experimental verification of generalized eigenstate thermalization hypothesis in an integrable system

Driven Gaussian quantum walks

Quantum Critical Lines in the Ground State Phase Diagram of Spin‐1/2 Frustrated Transverse‐Field Ising Chains

Contact Info

Product

Resources

About