Enhancing quantum coherence with short-range correlated disorder

Capuzzi, P.; Gattobigio, M.; Vignolo, Patrizia

doi:10.1103/physreva.92.053622

Cited by 4 publications

(14 citation statements)

References 25 publications

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“…3 we compare the time evolution of a density perturbation in an UN-RAND lattice and in a 2D-DRDM one for t = 3t, different values of ∆ and p = 0.25. We consider a system with a weak interaction U/t = 10 −2 and average number of particles per site n i = 5 [6]. For any value of ∆ in the UN-RAND model, the density perturbation distorts as it moves through the system; whereas in the 2D-DRDM, if ∆ is close to the resonant value ∆ res = 32t, the density perturbation propagates for a long time without a pronounced dispersion.…”

Section: Density Wave Propagationmentioning

confidence: 99%

“…If the Hamiltonian parameters are tuned * Electronic address: capuzzi@df.uba.ar † Electronic address: Patrizia.Vignolo@inphyni.cnrs.fr so that the resonance energy matches the ground-state energy, the ground state is not affected by the disorder, even in the presence of weak interactions. The density homogenization induced by the resonance drives the superfluid fraction [6]. This happens at the ground-state energy, but, as soon as the system is perturbed, higher energy states are involved, and it is not straightforward to derive the response of the system.…”

Section: Introductionmentioning

confidence: 99%

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Density wave propagation in a two-dimensional random dimer potential: From a single to a bipartite square lattice

Capuzzi¹,

Vignolo²

2020

Phys. Rev. A

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We study the propagation of a density perturbation in a weakly interacting boson gas confined on a lattice and in the presence of square dimerized impurities. Such a two-dimensional random-dimer model (2D-DRDM), previously introduced in [Capuzzi et al., Phys. Rev. A 92, 053622 (2015)], is the disorder transition from a single square lattice, where impurities are absent, to a bipartite square lattice, where the number of impurities is maximum and coincides with half the number of lattice sites. We show that disorder correlations can play a crucial role in the dynamics for a broad range of parameters by allowing density fluctuations to propagate in the 2D-DRDM lattice, even in the limit of strong disorder. In such a regime, the propagation speed depends on the percentage of impurities, interpolating between the speed in a single monoperiodic lattice and that in a bipartite one.PACS numbers:

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Section: Density Wave Propagationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Density wave propagation in a two-dimensional random dimer potential: From a single to a bipartite square lattice

Capuzzi¹,

Vignolo²

2020

Phys. Rev. A

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“…and ù=r 2 /r 1 . For any eigenvalue of the momentum q, let x(q, s) be the sth zero of the crossproduct of Bessel functions (49), with x q s x q s , 1 ,…”

Section: Radial Part Of the Schrödinger Equationmentioning

confidence: 99%

“…The values x(q, s) can be obtained by solving numerically (49); for larger values of s one can also use the asymptotic expansion provided by the McMahon formula [65].…”

Section: Radial Part Of the Schrödinger Equationmentioning

confidence: 99%

“…In the field of cold atoms, the use of correlated disorder to produce spectral shaping of the localisation length in 2D and 3D experiments was considered in [47,48]. More recently, the effects of short-range correlations were considered for a Bose gas confined on a 2D square lattice [49]. Using a 2D generalisation of the dual dimer random model, the authors showed that short-range correlations of the disorder can enhance quantum coherence in a weakly interacting many-body system.…”

Section: Introductionmentioning

confidence: 99%

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Localisation and transport in bidimensional random models with separable Hamiltonians

et al. 2019

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We consider two bidimensional random models characterised by the following features: (a) their Hamiltonians are separable in polar coordinates and (b)the random part of the potential depends either on the angular coordinate or on the radial one, but not on both. The disorder correspondingly localises the angular or the radial part of the eigenfunctions. We analyse the analogies and the differences which exist between the selected 2D models and their 1D counterparts. We show how the analogies allow one to use correlated disorder to design a localisation length with pre-defined energy dependence and to produce directional localisation of the wavefunctions in models with angular disorder. We also discuss the importance of finite-size and resonance effects in shaping the eigenfunctions of the model with angular disorder; for the model with disorder associated to the radial variable we show under what conditions the localisation length coincides with the expression valid in the 1D case.

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Anderson localization in optical lattices with correlated disorder

Fratini

Pilati

2015

Phys. Rev. A

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We study the Anderson localization of atomic gases exposed to simple-cubic optical lattices with a superimposed disordered speckle pattern. The two mobility edges in the first band and the corresponding critical filling factors are determined as a function of the disorder strength, ranging from vanishing disorder up to the critical disorder intensity where the two mobility edges merge and the whole band becomes localized. Our theoretical analysis is based both on continuous-space models which take into account the details of the spatial correlation of the speckle pattern, and also on a simplified tight-binding model with an uncorrelated distribution of the on-site energies. The mobility edges are computed via the analysis of the energy-level statistics, and we determine the universal value of the ratio between consecutive level spacings at the mobility edge. We analyze the role of the spatial correlation of the disorder, and we also discuss a qualitative comparison with available experimental data for interacting atomic Fermi gases measured in the moderate interaction regime.Comment: 9 pages, 7 figure

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Enhancing quantum coherence with short-range correlated disorder

Cited by 4 publications

References 25 publications

Density wave propagation in a two-dimensional random dimer potential: From a single to a bipartite square lattice

Density wave propagation in a two-dimensional random dimer potential: From a single to a bipartite square lattice

Localisation and transport in bidimensional random models with separable Hamiltonians

Anderson localization in optical lattices with correlated disorder

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