TY - JOUR
T1 - Prethermalization and dynamical transition in an isolated trapped ion spin chain
JF - New Journal of Physics
Y1 - 2013
A1 - Zhe-Xuan Gong
A1 - L. -M. Duan
AB - 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.
VL - 15
U4 - 113051
UR - http://arxiv.org/abs/1305.0985v1
CP - 11
J1 - New J. Phys.
U5 - 10.1088/1367-2630/15/11/113051
ER -
TY - JOUR
T1 - Quantum Logic between Remote Quantum Registers
JF - Physical Review A
Y1 - 2013
A1 - Norman Y. Yao
A1 - Zhe-Xuan Gong
A1 - Chris R. Laumann
A1 - Steven D. Bennett
A1 - L. -M. Duan
A1 - Mikhail D. Lukin
A1 - Liang Jiang
A1 - Alexey V. Gorshkov
AB - 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.
VL - 87
UR - http://arxiv.org/abs/1206.0014v1
CP - 2
J1 - Phys. Rev. A
U5 - 10.1103/PhysRevA.87.022306
ER -
TY - JOUR
T1 - Reply to Comment on "Space-Time Crystals of Trapped Ions
Y1 - 2012
A1 - Tongcang Li
A1 - Zhe-Xuan Gong
A1 - Zhang-qi Yin
A1 - H. T. Quan
A1 - Xiaobo Yin
A1 - Peng Zhang
A1 - L. -M. Duan
A1 - Xiang Zhang
AB - This is a reply to the comment from Patrick Bruno (arXiv:1211.4792) on our paper (Phys. Rev. Lett. 109, 163001 (2012)).
UR - http://arxiv.org/abs/1212.6959v2
U5 - http://dx.doi.org/10.1103/PhysRevLett.109.163001
ER -
TY - JOUR
T1 - Comment on "Foundation of Statistical Mechanics under Experimentally Realistic Conditions"
Y1 - 2011
A1 - Zhe-Xuan Gong
A1 - L. -M. Duan
AB - 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.
UR - http://arxiv.org/abs/1109.4696v1
ER -
TY - JOUR
T1 - Dynamics of Overhauser Field under nuclear spin diffusion in a quantum dot
JF - New Journal of Physics
Y1 - 2011
A1 - Zhe-Xuan Gong
A1 - Zhang-qi Yin
A1 - L. -M. Duan
AB - 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.
VL - 13
U4 - 033036
UR - http://arxiv.org/abs/0912.4322v1
CP - 3
J1 - New J. Phys.
U5 - 10.1088/1367-2630/13/3/033036
ER -
TY - JOUR
T1 - Robust Quantum State Transfer in Random Unpolarized Spin Chains
JF - Physical Review Letters
Y1 - 2011
A1 - Norman Y. Yao
A1 - Liang Jiang
A1 - Alexey V. Gorshkov
A1 - Zhe-Xuan Gong
A1 - Alex Zhai
A1 - L. -M. Duan
A1 - Mikhail D. Lukin
AB - 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.
VL - 106
UR - http://arxiv.org/abs/1011.2762v2
CP - 4
J1 - Phys. Rev. Lett.
U5 - 10.1103/PhysRevLett.106.040505
ER -
TY - JOUR
T1 - Temperature driven structural phase transition for trapped ions and its experimental detection
JF - Physical Review Letters
Y1 - 2010
A1 - Zhe-Xuan Gong
A1 - G. -D. Lin
A1 - L. -M. Duan
AB - 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'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.
VL - 105
UR - http://arxiv.org/abs/1009.0089v1
CP - 26
J1 - Phys. Rev. Lett.
U5 - 10.1103/PhysRevLett.105.265703
ER -