



@article {2529,
	title = {Programmable Quantum Simulations of Spin Systems with Trapped Ions},
	year = {2019},
	month = {12/17/2019},
	abstract = {<p>Laser-cooled and trapped atomic ions form an ideal standard for the simulation of interacting quantum spin models. Effective spins are represented by appropriate internal energy levels within each ion, and the spins can be measured with near-perfect efficiency using state-dependent fluorescence techniques. By applying optical fields that exert optical dipole forces on the ions, their Coulomb interaction can be modulated in ways that give rise to long-range and tunable spin-spin interactions that can be reconfigured by shaping the spectrum and pattern of the laser fields. Here we review the theoretical mapping of atomic ions to interacting spin systems, the experimental preparation of complex equilibrium states, and the study of dynamical processes of this many-body interacting quantum system. The use of such quantum simulators for studying spin models may inform our understanding of exotic quantum materials and shed light on interacting quantum systems that cannot be modeled with conventional computers.\&nbsp;</p>},
	url = {https://arxiv.org/abs/1912.07845},
	author = {C. Monroe and W. C. Campbell and L. -M. Duan and Z. -X. Gong and Alexey V. Gorshkov and P. Hess and R. Islam and K. Kim and G. Pagano and P. Richerme and C. Senko and N. Y. Yao}
}
@article {1485,
	title = {Prethermalization and dynamical transition in an isolated trapped ion  spin chain
},
	journal = {New Journal of Physics},
	volume = {15},
	year = {2013},
	month = {2013/11/26},
	pages = {113051},
	abstract = {  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.
},
	doi = {10.1088/1367-2630/15/11/113051},
	url = {http://arxiv.org/abs/1305.0985v1},
	author = {Zhe-Xuan Gong and L. -M. Duan}
}
@article {1199,
	title = {Quantum Logic between Remote Quantum Registers},
	journal = {Physical Review A},
	volume = {87},
	year = {2013},
	month = {2013/2/6},
	abstract = {  We analyze two approaches to quantum state transfer in solid-state spin
systems. First, we consider unpolarized spin-chains and extend previous
analysis to various experimentally relevant imperfections, including quenched
disorder, dynamical decoherence, and uncompensated long range coupling. In
finite-length chains, the interplay between disorder-induced localization and
decoherence yields a natural optimal channel fidelity, which we calculate.
Long-range dipolar couplings induce a finite intrinsic lifetime for the
mediating eigenmode; extensive numerical simulations of dipolar chains of
lengths up to L=12 show remarkably high fidelity despite these decay processes.
We further consider the extension of the protocol to bosonic systems of coupled
oscillators. Second, we introduce a quantum mirror based architecture for
universal quantum computing which exploits all of the spins in the system as
potential qubits. While this dramatically increases the number of qubits
available, the composite operations required to manipulate "dark" spin qubits
significantly raise the error threshold for robust operation. Finally, as an
example, we demonstrate that eigenmode-mediated state transfer can enable
robust long-range logic between spatially separated Nitrogen-Vacancy registers
in diamond; numerical simulations confirm that high fidelity gates are
achievable even in the presence of moderate disorder.
},
	doi = {10.1103/PhysRevA.87.022306},
	url = {http://arxiv.org/abs/1206.0014v1},
	author = {Norman Y. Yao and Zhe-Xuan Gong and Chris R. Laumann and Steven D. Bennett and L. -M. Duan and Mikhail D. Lukin and Liang Jiang and Alexey V. Gorshkov}
}
@article {1491,
	title = {Reply to Comment on "Space-Time Crystals of Trapped Ions},
	year = {2012},
	month = {2012/10/15},
	abstract = {  This is a reply to the comment from Patrick Bruno (arXiv:1211.4792) on our
paper (Phys. Rev. Lett. 109, 163001 (2012)).
},
	doi = {http://dx.doi.org/10.1103/PhysRevLett.109.163001},
	url = {http://arxiv.org/abs/1212.6959v2},
	author = {Tongcang Li and Zhe-Xuan Gong and Zhang-qi Yin and H. T. Quan and Xiaobo Yin and Peng Zhang and L. -M. Duan and Xiang Zhang}
}
@article {1484,
	title = {Comment on "Foundation of Statistical Mechanics under Experimentally  Realistic Conditions"
},
	year = {2011},
	month = {2011/09/22},
	abstract = {  Reimann [Phys. Rev. Lett. 101, 190403 (2008)] claimed that generic isolated
macroscopic quantum system will equilibrate under experimentally realistic
conditions by proving a theorem. We here show that the proof is invalid for
most many-body systems and is unable to demonstrate equilibration in realistic
experiment.
},
	url = {http://arxiv.org/abs/1109.4696v1},
	author = {Zhe-Xuan Gong and L. -M. Duan}
}
@article {1488,
	title = {Dynamics of Overhauser Field under nuclear spin diffusion in a quantum  dot
},
	journal = {New Journal of Physics},
	volume = {13},
	year = {2011},
	month = {2011/03/25},
	pages = {033036},
	abstract = {  The coherence of electron spin can be significantly enhanced by locking the
Overhauser field from nuclear spins using the nuclear spin preparation. We
propose a theoretical model to calculate the long time dynamics of the
Overhauser field under intrinsic nuclear spin diffusion in a quantum dot. We
obtain a simplified diffusion equation that can be numerically solved and show
quantitatively how the Knight shift and the electron-mediated nuclear spin
flip-flop affect the nuclear spin diffusion. The results explain several recent
experimental observations, where the decay time of Overhauser field is measured
under different configurations, including variation of the external magnetic
field, the electron spin configuration in a double dot, and the initial nuclear
spin polarization rate.
},
	doi = {10.1088/1367-2630/13/3/033036},
	url = {http://arxiv.org/abs/0912.4322v1},
	author = {Zhe-Xuan Gong and Zhang-qi Yin and L. -M. Duan}
}
@article {1196,
	title = {Robust Quantum State Transfer in Random Unpolarized Spin Chains},
	journal = {Physical Review Letters},
	volume = {106},
	year = {2011},
	month = {2011/1/27},
	abstract = {  We propose and analyze a new approach for quantum state transfer between
remote spin qubits. Specifically, we demonstrate that coherent quantum coupling
between remote qubits can be achieved via certain classes of random,
unpolarized (infinite temperature) spin chains. Our method is robust to
coupling strength disorder and does not require manipulation or control over
individual spins. In principle, it can be used to attain perfect state transfer
over arbitrarily long range via purely Hamiltonian evolution and may be
particularly applicable in a solid-state quantum information processor. As an
example, we demonstrate that it can be used to attain strong coherent coupling
between Nitrogen-Vacancy centers separated by micrometer distances at room
temperature. Realistic imperfections and decoherence effects are analyzed.
},
	doi = {10.1103/PhysRevLett.106.040505},
	url = {http://arxiv.org/abs/1011.2762v2},
	author = {Norman Y. Yao and Liang Jiang and Alexey V. Gorshkov and Zhe-Xuan Gong and Alex Zhai and L. -M. Duan and Mikhail D. Lukin}
}
@article {1489,
	title = {Temperature driven structural phase transition for trapped ions and its  experimental detection
},
	journal = {Physical Review Letters},
	volume = {105},
	year = {2010},
	month = {2010/12/29},
	abstract = {  A Wigner crystal formed with trapped ion can undergo structural phase
transition, which is determined only by the mechanical conditions on a
classical level. Instead of this classical result, we show that through
consideration of quantum and thermal fluctuation, a structural phase transition
can be solely driven by change of the system{\textquoteright}s temperature. We determine a
finite-temperature phase diagram for trapped ions using the renormalization
group method and the path integral formalism, and propose an experimental
scheme to observe the predicted temperature-driven structural phase transition,
which is well within the reach of the current ion trap technology.
},
	doi = {10.1103/PhysRevLett.105.265703},
	url = {http://arxiv.org/abs/1009.0089v1},
	author = {Zhe-Xuan Gong and G. -D. Lin and L. -M. Duan}
}
