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The spin squeezing protocols allow the dynamical generation of massively correlated quantum many-body states, which can be utilized in entanglement-enhanced metrology and technologies. We study a quantum simulator generating twisting…

The notion of spin squeezing involves reduction in the uncertainty of a component of the spin vector below a certain limit. This aspect has been studied earlier for pure and mixed states of definite spin. In this paper, this study has been…

Quantum Physics · Physics 2009-11-07 A. R. Usha Devi , K. S. Mallesh , Mahmoud A. A. Sbaih , K. B. Nalini , G Ramachandran

Realizable spin models are investigated in a two superconducting flux qubit system. It is shown that a specific adjustment of system parameters in the two flux qubit system makes it possible to realize an artificial two-spin system that…

Mesoscale and Nanoscale Physics · Physics 2007-06-19 Qian Qian Shi , Sam Young Cho , Bo Li , Mun Dae Kim

Spin squeezing is vitally important in quantum metrology and quantum information science. The noise reduction resulting from spin squeezing can surpass the standard quantum limit and even reach the Heisenberg Limit (HL) in some special…

Quantum Physics · Physics 2023-08-25 Zhiyao Hu , Qixian Li , Xuanchen Zhang , Long-Gang Huang , He-bin Zhang , Yong-Chun Liu

Two-mode squeezed states, which are entangled states with bipartite quantum correlations in continuous-variable systems, are crucial in quantum information processing and metrology. Recently, continuous-variable quantum computing with the…

Quantum Physics · Physics 2023-11-10 Wui Seng Leong , Mingjie Xin , Zilong Chen , Yu Wang , Shau-Yu Lan

We study the non-equilibrium dynamics of a quantum spin 1/2 XXZ model confined in a two-dimensional bi-layer system, with couplings mediated by inverse power-law interactions, falling off with distance $r$ as $1/r^{\alpha}$, and…

Quantum Physics · Physics 2024-06-27 Arman Duha , Thomas Bilitewski

Using a quantum theory for an ensemble of three-level atoms (lambda) placed in an optical cavity abd driven by electromagnetic fields, we show that the long-lived spin associated with the ground state sublevels can be squeezed. Two kinds of…

Quantum Physics · Physics 2009-11-07 A. Dantan , M. Pinard , V. Josse , N. Nayak , P. R. Berman

We investigate the generation of entanglement (spin squeezing) in an optical-transition atomic clock through the coupling to a vacuum electromagnetic field that is enhanced by an optical cavity. We show that if each atom is prepared in a…

Quantum Physics · Physics 2017-11-22 Jiazhong Hu , Wenlan Chen , Zachary Vendeiro , Alban Urvoy , Boris Braverman , Vladan Vuletić

Squeezing ensemble of spins provides a way to surpass the standard quantum limit (SQL) in quantum metrology and test the fundamental physics as well, and therefore attracts broad interest. Here we propose an experimentally accessible…

Quantum Physics · Physics 2021-04-07 Keyu Xia

Squeezed spin states have important applications in quantum metrology and sensing. It has been shown by S{\o}rensen and M{\o}lmer [Phys. Rev. A 66, 022314(2002)] that an effective one-axis-twisting interaction can be realized in a cavity…

Quantum Physics · Physics 2019-05-08 Gang Liu , Ya-Ni Wang , Li-Fen Yan , Nian-Quan Jiang , Wei Xiong , Ming-Feng Wang

This study investigates spin squeezed states in nuclear magnetic resonance (NMR) quadrupolar systems with spins $I=3/2$ and $I=7/2$ at room temperature, taking into account the effects of relaxation on the dynamics. The origin of spin…

Squeezing of collective atomic spins has been shown to improve the sensitivity of atomic clocks and magnetometers to levels significantly below the standard quantum limit. In most cases the requisite atom-atom entanglement has been…

At absolute zero temperature, thermal noise vanishes when a physical system is in its ground state, but quantum noise remains as a fundamental limit to the accuracy of experimental measurements. Such a limitation, however, can be mitigated…

Condensed Matter · Physics 2009-11-10 J. Zhao , A. V. Bragas , D. J. Lockwood , R. Merlin

We describe an efficient numerical method for simulating the dynamics of interacting spin ensembles in the presence of dephasing and decay. The method builds on the discrete truncated Wigner approximation for isolated systems, which…

Quantum Physics · Physics 2022-02-01 Julian Huber , Ana Maria Rey , Peter Rabl

We investigate the presence of spin- and planar- squeezing in generalized superpositions of atomic (or spin) coherent states (ACS). Spin-squeezing has been shown to be a useful tool in determining the presence of entanglement in…

We study a bulk fermionic dipolar molecular gas in the quantum degenerate regime confined in a two-dimensional geometry. We consider two rotational states that encode a spin 1/2 degree of freedom. We derive a long-range interacting XXZ…

We analyze a model for spin squeezing based on the so-called counter-twisting Hamiltonian, including the effects of dissipation and finite system size. We discuss the conditions under which the Heisenberg limit, i.e. phase sensitivity…

Quantum Physics · Physics 2009-11-07 A. André , M. D. Lukin

A method for generating a mesoscopic superposition state of the collective spin variable of a gas of atoms is proposed. The state consists of a superposition of the atomic spins pointing in two slightly different directions. It is obtained…

Quantum Physics · Physics 2009-11-10 S. Massar , E. S. Polzik

We analyze the collective spin noise in interacting spin systems. General expressions are derived for the short time behaviour of spin systems with general spin-spin interactions, and we suggest optimum experimental conditions for the…

Quantum Physics · Physics 2009-11-07 Xiaoguang Wang , Anders S. Sorensen , Klaus Molmer

A semiclassical approach is proposed to calculate the collective potential and mass parameters to formulate a collective Hamiltonian capable of describing the wobbling motion in both even-even and odd-mass systems. By diagonalizing the…

Nuclear Theory · Physics 2024-01-15 Q. B. Chen , S. Frauendorf