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Related papers: Magnetic field sensors using 13-spin cat states

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Quantum phenomena such as entanglement provide powerful resources for enhancing classical sensing. Here, we theoretically show that collective entanglement of spin qubits, arising from a condensation of particle-hole pairs, can strongly…

We study the entanglement content of a class of mesoscopic tunable magnetic systems. The systems are closed finite spin-1/2 chains with ferromagnetic nearest-neighbor interactions frustrated by antiferromagnetic next-nearest-neighbor…

Statistical Mechanics · Physics 2009-06-10 Masudul Haque , V. Ravi Chandra , Jayendra N. Bandyopadhyay

We investigate the simultaneous estimation of the intensity and the orientation of a magnetic field by the multi-parameter quantum Fisher information matrix. A general expression is achieved for the simultaneous estimation precision of the…

Quantum Physics · Physics 2019-08-13 Dong Xie , Chunling Xu

The single-molecule magnets {Mn$_{70}$} and {Mn$_{84}$} are characterized by a 14-site unit cell with $S=2$ spin sites arranged in a circular geometry. Experimentally, these systems exhibit a magnetic ground state with a notably low total…

Strongly Correlated Electrons · Physics 2025-02-21 R. Rausch , C. Karrasch

In this review, we describe the potentialities offered by the nuclear magnetic resonance (NMR) technique to explore at a microscopic level new quantum states of condensed matter induced by high magnetic fields. We focus on experiments…

Strongly Correlated Electrons · Physics 2017-11-30 Claude Berthier , Mladen Horvatić , Marc-Henri Julien , Hadrien Mayaffre , Steffen Krämer

Entanglement in a many-particle system can enable measurement sensitivities beyond that achievable by only classical correlations. For an ensemble of spins, all-to-all interactions are known to reshape the quantum projection noise, leading…

Quantum metrology employs quantum resources to enhance the measurement sensitivity beyond that can be achieved classically. While multi-photon entangled NOON states can in principle beat the shot-noise limit and reach the Heisenberg limit,…

Quantum entanglement has been generated and verified in cold-atom experiments and used to make atom-interferometric measurements below the shot-noise limit. However, current state-of-the-art cold-atom devices exploit separable (i.e.…

Quantum Physics · Physics 2021-04-13 Stuart S. Szigeti , Onur Hosten , Simon A. Haine

The entangled "Schrodinger's cat state" of a quantum and its measurement apparatus is not a paradoxical superposition of states but is instead a non-paradoxical superposition of nonlocal coherent correlations between states: An un-decayed…

Quantum Physics · Physics 2022-06-14 Art Hobson

We demonstrate the creation of entangled, spin-squeezed states using a collective, or joint, measurement and real-time feedback. The pseudospin state of an ensemble of $N= 5\times 10^4$ laser-cooled $^{87}$Rb atoms is deterministically…

Atomic Physics · Physics 2016-03-09 Kevin C. Cox , Graham P. Greve , Joshua M. Weiner , James K. Thompson

Reliable methods for the classification and quantification of quantum entanglement are fundamental to understanding its exploitation in quantum technologies. One such method, known as Separable Neural Network Quantum States (SNNS), employs…

Quantum Physics · Physics 2021-06-15 Cillian Harney , Mauro Paternostro , Stefano Pirandola

Quantum information processing by liquid-state NMR spectroscopy uses pseudo-pure states to mimic the evolution and observations on true pure states. A new method of preparing pseudo-pure states is described, which involves the selection of…

Quantum Physics · Physics 2009-11-06 Yehuda Sharf , Timothy F. Havel , David G. Cory

We consider systems of interacting spins and study the entanglement that can be localized, on average, between two separated spins by performing local measurements on the remaining spins. This concept of Localizable Entanglement (LE) leads…

Quantum Physics · Physics 2007-05-23 M. Popp , F. Verstraete , M. A. Martin-Delgado , J. I. Cirac

We show that the two-axis counter twisting interaction squeezes a coherent spin state into three states of interest in quantum information, namely, the twin-Fock state, the equally-weighted superposition state, and the state that achieves…

Quantum Physics · Physics 2015-01-07 Emi Yukawa , Gerard Milburn , Masahito Ueda , Kae Nemoto

We consider a finite two-dimensional Heisenberg triangular spin lattice at different degrees of anisotropy coupled to a dissipative Lindblad environment obeying the Born-Markovian constrain at finite temperature. We show how applying an…

Quantum Physics · Physics 2020-09-18 Gehad Sadiek , Samaher Almalki

Nonclassical states are essential for optics-based quantum information processing, but their fragility limits their utility for practical scenarios in which loss and noise inevitably degrade, if not destroy, nonclassicality. Exploiting…

Quantum Physics · Physics 2015-03-25 Zheshen Zhang , Sara Mouradian , Franco N. C. Wong , Jeffrey H. Shapiro

Quantum sensors have been shown to be superior to their classical counterparts in terms of resource efficiency. Such sensors have traditionally used the time evolution of special forms of initially entangled states, adaptive measurement…

Quantum Physics · Physics 2020-03-06 Gareth Siôn Jones , Sougato Bose , Abolfazl Bayat

The ability to sensitively detect charges under ambient conditions would be a fascinating new tool benefitting a wide range of researchers across disciplines. However, most current techniques are limited to low-temperature methods like…

The control over quantum states in atomic systems has led to the most precise optical atomic clocks to date. Their sensitivity is currently bounded by the standard quantum limit, a fundamental floor set by quantum mechanics for uncorrelated…

Localized spins in the solid state are attracting widespread attention as highly sensitive quantum sensors with nanoscale spatial resolution and fascinating applications. Recently, adaptive measurements were used to improve the dynamic…

Quantum Physics · Physics 2018-09-26 Yi-Hao Zhang , Wen Yang