Dissipative phase transition in a central spin system

Kessler, Eric; Giedke, G.; İmamoğlu, Ataç; Yelin, Susanne F.; Lukin, Mikhail D.; Cirac, J. I.

doi:10.1103/physreva.86.012116

Cited by 320 publications

(354 citation statements)

References 55 publications

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“…As a first example that this may be possible, the creation of squeezed states of the nuclear spin bath in quantum dots was recently proposed, using microwave irradiation 98,99 . In spin squeezing, the uncertainty of one component of the (total) spin is reduced below the uncertainty limit at the expense of increased uncertainty in an orthogonal component 100 .…”

Section: Future Directions and Other Materialsmentioning

confidence: 99%

Nuclear spin effects in semiconductor quantum dots

et al. 2013

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Section: Future Directions and Other Materialsmentioning

confidence: 99%

Nuclear spin effects in semiconductor quantum dots

et al. 2013

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“…Our criteria thus provide an effective means of detecting the degree of entanglement in spin squeezing experiments like atomic ensembles. The procedure is, however, equally applicable to other physical systems [21,[31][32][33]. Moreover, since the improvement of atomic clocks is related to the spin squeezing parameter, our results suggest that there exist unentangled states which would give a better performance of atomic clocks than |CSS .…”

mentioning

confidence: 70%

“…The present example is motivated by the specific physical systems of atomic ensembles probed by Gaussian laser beams. However, spin squeezing is used in other physical systems [31][32][33] as well, where the distribution may be even more asymmetric, resulting in a larger difference between the criteria.…”

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confidence: 99%

Multipartite entanglement detection with nonsymmetric probing

et al. 2017

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We show that spin squeezing criteria commonly used for entanglement detection can be erroneous, if the probe is not symmetric. We then derive a lower bound on squeezing for separable states in spin systems probed asymmetrically. Using this we further develop a procedure that allows us to verify the degree of entanglement of a quantum state in the spin system. Finally, we apply our method for entanglement verification to existing experimental data, and use it to prove the existence of tri-partite entanglement in a spin squeezed atomic ensemble.Entanglement is a fundamental resource for proving nonclassicality of nature, and is a key feature for developing quantum technologies. It was first used experimentally for proving the breakdown of local realism [1,2], and has now become a practical ingredient in quantum information science and metrology [3]. As such, it is crucial to discern between separable and entangled systems. Unfortunately, this is not always straightforward; even though several criteria exist [4][5][6], it may be hard to experimentally verify that a state is entangled. Hence, there is a need for simple, practical procedures for proving that a system is entangled. An example of such a criterion is spin squeezing [7][8][9], which has often been used to probe entanglement in multi-particle systems [10]. One of its major advantages is that it relies on measuring only two observables: the mean spin and the fluctuations perpendicular to it. This makes it ideally suited for systems where complete control over all degrees of freedom is hard to achieve. Measuring that the noise is squeezed below a certain bound is then a sufficient criterion for proving entanglement [11][12][13][14][15][16][17][18][19]. Due to the simplicity of this approach, it has been employed to show even multi-partite entanglement in a wide range of experiments [20][21][22][23][24]. However, an inherent assumption in the entanglement criteria based on spin squeezing is that all particles are probed with equal strength. In many practical situations this is a very good approximation [21,23], but in others this is far from reality. As an example, consider a Gaussian beam probing a collection of trapped atoms. If the waist of the laser beam is much smaller than the size of the cloud, the atoms will have an asymmetric interaction with the light. This asymmetry leads to minor modifications of the interaction dynamics if suitable weighted operators are introduced [25,26]. For entanglement detection in the ensemble, however, the effect of such asymmetry may be much more severe and has so far not been investigated.In this article, we consider the effect of asymmetric probing on the entanglement criteria. We first consider a simple generalization of the standard squeezing criterion and show that it is no longer a suitable method for verifying entanglement. To overcome this problem we develop new entanglement criteria, that can accommodate the asymmetric probing of the particles. We show that our criteria are sufficient for detection of bi-partite...

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“…It is interesting to note that, for any κ, one can drive the system strong enough to overcome thermalization and enter the phase where the transition takes place. Equation (38) is applicable to all values of the driving , features the correct results in the limits → 0 and → ∞, and correctly captures the existence of a nonequilibrium phase transition in the model. The profile of |α| 2 obtained by the numerical solution in the close vicinity δ /κ 0.1 of crit , though, is more complex than the linear slope which follows from Eq.…”

Section: Analytical Interpolation With Displaced Thermal Statesmentioning

confidence: 99%

“…(5), and the corresponding open system with particle losses. Moreover, the relation between equilibrium and nonequilibrium phases of a model [38] could be investigated systematically. More generally, the flexibility in the implementation of the jump operators could be leveraged to study the effects of the competition between different terms in the nonunitary contribution L to the Liouvillian in a driven-dissipative nonequilibrium scenario with stable stationary states, and no immediate condensed matter counterpart.…”

Section: ∂ T ρ(T) = −I[ĥρ(t)] + L[ρ(t)]mentioning

confidence: 99%

Reservoir engineering and dynamical phase transitions in optomechanical arrays

et al. 2012

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We study the driven-dissipative dynamics of photons interacting with an array of micromechanical membranes in an optical cavity. Periodic membrane driving and phonon creation result in an effective photon-numberconserving nonunitary dynamics, which features a steady state with long-range photonic coherence. If the leakage of photons out of the cavity is counteracted by incoherent driving of the photonic modes, we show that the system undergoes a dynamical phase transition to the state with long-range coherence. A minimal system, composed of two micromechanical membranes in a cavity, is studied in detail, and it is shown to be a realistic setup where the key processes of the driven-dissipative dynamics can be seen.

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Dissipative phase transition in a central spin system

Cited by 320 publications

References 55 publications

Nuclear spin effects in semiconductor quantum dots

Nuclear spin effects in semiconductor quantum dots

Multipartite entanglement detection with nonsymmetric probing

Reservoir engineering and dynamical phase transitions in optomechanical arrays

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