Abstract
Eigenstate Thermalization Hypothesis(ETH) has played a pivotal role in understanding ergodicity and its breaking in isolated quantum many-body systems. Recent experiment on 51-atom Rydberg quantum simulator and subsequent theoretical analysis have shown that hardcore kinetic constraint can lead to weak ergodicity breaking. In this work, we demonstrate, using 1d spin-1 PXP chains, that miscellaneous type of ergodicity can be realized by adjusting the hardcore constraints between different components of nearest neighbor spins. This includes ETH violation due to emergent shattering of Hilbert space into exponentially many subsectors of various sizes, a novel form of non-integrability with an extensive number of local conserved quantities and strong ergodicity. We analyze these different forms of ergodicity and study their impact on the non-equilibrium dynamics of a Z2 initial state. We use forward scattering approximation (FSA) to understand the amount of Z2-oscillation present in these models. Our work shows that not only ergodicity breaking but an appropriate choice of constraints can lead to restoration of ergodicity as well.
Highlights
Eigenstate thermalization hypothesis (ETH) offers the most widely accepted mechanism of thermalization of local observables in out-of-equilibrium closed quantum many-body systems [1,2,3,4,5]
In this work we focus on spin-1 PXP model [26,27] which is defined by the Hamiltonian: H = − i PSixP in a chain of L sites where the local Hilbert space is spanned by the eigenstates of Sz (|m ≡ |−, |0, |+ for m = −1, 0, +1) and the operator P = i Pi,i+1 characterizes the constrained Hilbert space
If we further allow |+0 /|0+ type configurations, an extensive number of local conserved quantities arises. This does not make model II exactly solvable due to some degeneracies in the spectrum of the conserved quantities. We find that these conserved quantities can be used at most to label different sectors of model II which are nothing but disconnected patches of spin-1/2 PXP model of different sizes
Summary
Eigenstate thermalization hypothesis (ETH) offers the most widely accepted mechanism of thermalization of local observables in out-of-equilibrium closed quantum many-body systems [1,2,3,4,5]. An ETH satisfying system, prepared in an unentangled product state, gets strongly entangled quickly under its own dynamics, losing all the information of the initial state except the conserved quantities (e.g., total energy) These systems are usually strongly interacting in nature which makes the full quantum system, though well isolated from external environment, suffer from the presence of an indigenous heat bath. Anomalous oscillation from a density wave (Z2) state observed in a quench dynamics experiment using a 51-atom Rydberg quantum simulator [13] has revitalized the interest into the field of thermalization and its violation This phenomenon is understood by using spin-1/2 PXP model which hosts extensive number of ETH violating states with high Z2 overlap, dubbed as quantum many-body scars, in its spectrum [14,15].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
