Feedback-enhanced self-organization of atoms in an optical cavity

Иванов, Д. А.; Ivanova, T. Yu.

doi:10.1134/s0021364014190060

Cited by 16 publications

(20 citation statements)

References 29 publications

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“…Note that global quantum nondemolition measurements have been already proposed for molecules in low dimensions 46 , which can link these fields even closer. Observing the photons leaving the cavity allows us to continuously monitor the state of the atoms, precisely determining when the density wave is established without need of external feedback 19 41 47 . If , the amplitude of the density wave remains constant on a timescale larger than 1/ J .…”

Section: Resultsmentioning

confidence: 99%

Quantum measurement-induced antiferromagnetic order and density modulations in ultracold Fermi gases in optical lattices

Mazzucchi

Caballero-Benítez

Mekhov

2016

Sci Rep

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Ultracold atomic systems offer a unique tool for understanding behavior of matter in the quantum degenerate regime, promising studies of a vast range of phenomena covering many disciplines from condensed matter to quantum information and particle physics. Coupling these systems to quantized light fields opens further possibilities of observing delicate effects typical of quantum optics in the context of strongly correlated systems. Measurement backaction is one of the most funda- mental manifestations of quantum mechanics and it is at the core of many famous quantum optics experiments. Here we show that quantum backaction of weak measurement can be used for tailoring long-range correlations of ultracold fermions, realizing quantum states with spatial modulations of the density and magnetization, thus overcoming usual requirement for a strong interatomic interactions. We propose detection schemes for implementing antiferromagnetic states and density waves. We demonstrate that such long-range correlations cannot be realized with local addressing, and they are a consequence of the competition between global but spatially structured backaction of weak quantum measurement and unitary dynamics of fermions.

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Section: Resultsmentioning

confidence: 99%

Quantum measurement-induced antiferromagnetic order and density modulations in ultracold Fermi gases in optical lattices

Mazzucchi

Caballero-Benítez

Mekhov

2016

Sci Rep

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“…Nevertheless, the light field is usually described classically, while its quantum properties are left neglected. However, elevating the treatment of light to the quantum regime leads to many interesting phenomena not present with classical light; pioneering works in the field have already shown that these phenomena include non-destructive quantum measurement [3][4][5][6][7][8], self-organisation and other novel phase behaviour [9][10][11][12][13][14][15], as well as the possibility to engineer quantum states and dynamics, particularly through the measurement backaction effect [16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Probing and Manipulating Fermionic and Bosonic Quantum Gases with Quantum Light

Elliott

Mazzucchi

Kozłowski

et al. 2015

Atoms

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Abstract:We study the atom-light interaction in the fully quantum regime, with the focus on off-resonant light scattering into a cavity from ultracold atoms trapped in an optical lattice. The detection of photons allows the quantum nondemolition (QND) measurement of quantum correlations of the atomic ensemble, distinguishing between different quantum states. We analyse the entanglement between light and matter and show how it can be exploited for realising multimode macroscopic quantum superpositions, such as Schrödinger cat states, for both bosons and fermions. We provide examples utilising different measurement schemes and study their robustness to decoherence. Finally, we address the regime where the optical lattice potential is a quantum dynamical variable and is modified by the atomic state, leading to novel quantum phases and significantly altering the phase diagram of the atomic system.

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“…) and the quantum jumps can counteract the damping, driving the atomic system towards states with high population imbalance. In order to prove this, we describe the average effect of a quantum jump on the width of the atomic distribution and the relative imbalance as (42) and (44). From these expressions we find that the average photocurrent affects b 2 and z 0 as ( )( ( )…”

Section: Case ¹ Jmentioning

confidence: 90%

Collective dynamics of multimode bosonic systems induced by weak quantum measurement

et al. 2016

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In contrast to the fully projective limit of strong quantum measurement, where the evolution is locked to a small subspace (quantum Zeno dynamics), or even frozen completely (quantum Zeno effect), the weak non-projective measurement can effectively compete with standard unitary dynamics leading to nontrivial effects. Here we consider global weak measurement addressing collective variables, thus preserving quantum superpositions due to the lack of which path information. While for certainty we focus on ultracold atoms, the idea can be generalized to other multimode quantum systems, including various quantum emitters, optomechanical arrays, and purely photonic systems with multiple-path interferometers (photonic circuits). We show that light scattering from ultracold bosons in optical lattices can be used for defining macroscopically occupied spatial modes that exhibit long-range coherent dynamics. Even if the measurement strength remains constant, the quantum measurement backaction acts on the atomic ensemble quasi-periodically and induces collective oscillatory dynamics of all the atoms. We introduce an effective model for the evolution of the spatial modes and present an analytic solution showing that the quantum jumps drive the system away from its stable point. We confirm our finding describing the atomic observables in terms of stochastic differential equations.

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Feedback-enhanced self-organization of atoms in an optical cavity

Cited by 16 publications

References 29 publications

Quantum measurement-induced antiferromagnetic order and density modulations in ultracold Fermi gases in optical lattices

Quantum measurement-induced antiferromagnetic order and density modulations in ultracold Fermi gases in optical lattices

Probing and Manipulating Fermionic and Bosonic Quantum Gases with Quantum Light

Collective dynamics of multimode bosonic systems induced by weak quantum measurement

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