



01814nas a2200169   4500008004100000245006700041210006600108260001400174490000800188520130400196100001701500700002201517700002401539700002501563700001901588856003701607       2019                        eng d00aProbing ground-state phase transitions through quench dynamics0 aProbing groundstate phase transitions through quench dynamics  c9/11/20190 v1233 a<p>The study of quantum phase transitions requires the preparation of a many-body system near its ground state, a challenging task for many experimental systems. The measurement of quench dynamics, on the other hand, is now a routine practice in most cold atom platforms. Here we show that quintessential ingredients of quantum phase transitions can be probed directly with quench dynamics in integrable and nearly integrable systems. As a paradigmatic example, we study global quench dynamics in a transverse-field Ising model with either short-range or long-range interactions. When the model is integrable, we discover a new dynamical critical point with a non-analytic signature in the short-range correlators. The location of the dynamical critical point matches that of the quantum critical point and can be identified using a finite-time scaling method. We extend this scaling picture to systems near integrability and demonstrate the continued existence of a dynamical critical point detectable at prethermal time scales. Therefore, our method can be used to approximately locate the quantum critical point. The scaling method is also relevant to experiments with finite time and system size, and our predictions are testable in near-term experiments with trapped ions and Rydberg atoms.</p>1 aTitum, Paraj1 aIosue, Joseph, T.1 aGarrison, James, R.1 aGorshkov, Alexey, V.1 aGong, Zhe-Xuan  uhttps://arxiv.org/abs/1809.0637701399nas a2200157   4500008004100000245006700041210006600108260001400174490000800188520091600196100001901112700002301131700002501154700002501179856003701204       2014                        eng d00aPersistence of locality in systems with power-law interactions0 aPersistence of locality in systems with powerlaw interactions  c2014/7/160 v1133 a  Motivated by recent experiments with ultra-cold matter, we derive a new bound
on the propagation of information in $D$-dimensional lattice models exhibiting
$1/r^{\alpha}$ interactions with $\alpha>D$. The bound contains two terms: One
accounts for the short-ranged part of the interactions, giving rise to a
bounded velocity and reflecting the persistence of locality out to intermediate
distances, while the other contributes a power-law decay at longer distances.
We demonstrate that these two contributions not only bound but, except at long
times, \emph{qualitatively reproduce} the short- and long-distance dynamical
behavior following a local quench in an $XY$ chain and a transverse-field Ising
chain. In addition to describing dynamics in numerous intractable long-range
interacting lattice models, our results can be experimentally verified in a
variety of ultracold-atomic and solid-state systems.
1 aGong, Zhe-Xuan1 aFoss-Feig, Michael1 aMichalakis, Spyridon1 aGorshkov, Alexey, V.  uhttp://arxiv.org/abs/1401.6174v201207nas a2200145   4500008004100000245008800041210006900129260001500198300001100213490000700224520075600231100001900987700001801006856003701024       2013                        eng d00aPrethermalization and dynamical transition in an isolated trapped ion  spin chain
0 aPrethermalization and dynamical transition in an isolated trappe  c2013/11/26  a1130510 v153 a  We propose an experimental scheme to observe prethermalization and dynamical
transition in one-dimensional XY spin chain with long range interaction and
inhomogeneous lattice spacing, which can be readily implemented with the
recently developed trapped-ion quantum simulator. Local physical observables
are found to relax to prethermal values at intermediate time scale, followed by
complete relaxation to thermal values at much longer time. The physical origin
of prethermalization is explained by spotting a non-trivial structure in lower
half of the energy spectrum. The dynamical behavior of the system is shown to
cross difference phases when the interaction range is continuously tuned,
indicating the existence of dynamical phase transition.
1 aGong, Zhe-Xuan1 aDuan, L., -M.  uhttp://arxiv.org/abs/1305.0985v101592nas a2200205   4500008004100000245012500041210006900166260001500235520091800250100001801168700002001186700002601206700002001232700001901252700001901271700001801290700002101308700002001329856003701349       2012                        eng d00aPhotonic quantum simulation of ground state configurations of Heisenberg  square and checkerboard lattice spin systems
0 aPhotonic quantum simulation of ground state configurations of He  c2012/05/123 a  Photonic quantum simulators are promising candidates for providing insight
into other small- to medium-sized quantum systems. The available photonic
quantum technology is reaching the state where significant advantages arise for
the quantum simulation of interesting questions in Heisenberg spin systems.
Here we experimentally simulate such spin systems with single photons and
linear optics. The effective Heisenberg-type interactions among individual
single photons are realized by quantum interference at the tunable direction
coupler followed by the measurement process. The effective interactions are
characterized by comparing the entanglement dynamics using pairwise concurrence
of a four-photon quantum system. We further show that photonic quantum
simulations of generalized Heisenberg interactions on a four-site square
lattice and a six-site checkerboard lattice are in reach of current technology.
1 aMa, Xiao-song1 aDakic, Borivoje1 aKropatsche, Sebastian1 aNaylor, William1 aChan, Yang-hao1 aGong, Zhe-Xuan1 aDuan, Lu-ming1 aZeilinger, Anton1 aWalther, Philip  uhttp://arxiv.org/abs/1205.2801v101229nas a2200145   4500008004100000245011300041210006900154260001500223300001600238490000700254520074000261100001901001700001901020856004401039       2007                        eng d00aPractical scheme for quantum dense coding between three parties using  microwave radiation in trapped ions
0 aPractical scheme for quantum dense coding between three parties   c2007/03/28  a1245 - 12520 v403 a  We propose a practical scheme for implementing two-dimension quantum dense
coding (QDC) between three parties through manipulating three ions confined in
microtraps addressed by microwaves and assisted by a magnetic field gradient.
The ions in our scheme are not required to be strictly cooled to the
vibrational ground state because single-qubit and multi-qubit operations are
made via Ising terms, in which the vibrational modes of the ions remain
unchanged throughout the scheme, rendering our scheme robust to the heating of
the ions. We also present the detailed steps and parameters for implementing
the three-party QDC experimentally and show that the proposed scheme is within
the current techniques of ion-trap experiments.
1 aYang, Wen-Xing1 aGong, Zhe-Xuan  uhttp://arxiv.org/abs/quant-ph/0702062v1