Optical lattice experiments which probe the effect of disorder on superfluidity often use a speckle pattern for generating the disorder. Such speckle disorder is spatially correlated. While fermionic superfluidity in the presence of uncorrelated disorder is well studied, the impact of correlated disorder, particularly on thermal properties of the superfluid, is poorly understood. We provide a detailed study of the impact of speckle disorder, for varying speckle size and disorder magnitude, on the ground state and thermal properties of a Fermi superfluid. We work in the coupling regime of BCS-BEC crossover in a two-dimensional lattice. For a fixed disorder strength, an increase in speckle size leads to smoothening of the self-consistent background potential, increase in the critical disorder needed for a superfluid-insulator transition, and an increase in superfluid ${T}_{c}$ . Along with these hints at decrease in effective disorder, speckle correlations also suppress the superfluid gap and the gap formation temperature---effects normally associated with increasing disorder. We correlate these effects with the effective potential and the single-particle localization effects in the ground state.Optical lattice experiments which probe the effect of disorder on superfluidity often use a speckle pattern for generating the disorder. Such speckle disorder is spatially correlated. While fermionic superfluidity in the presence of uncorrelated disorder is well studied, the impact of correlated disorder, particularly on thermal properties of the superfluid, is poorly understood. We provide a detailed study of the impact of speckle disorder, for varying speckle size and disorder magnitude, on the ground state and thermal properties of a Fermi superfluid. We work in the coupling regime of BCS-BEC crossover in a two-dimensional lattice. For a fixed disorder strength, an increase in speckle size leads to smoothening of the self-consistent background potential, increase in the critical disorder needed for a superfluid-insulator transition, and an increase in superfluid ${T}_{c}$. Along with these hints at decrease in effective disorder, speckle correlations also suppress the superfluid gap and the gap formation temperature---effects normally associated with increasing disorder. We correlate these effects with the effective potential and the single-particle localization effects in the ground state.

arXiv:1810.03582Physical review. B./Physical review. BJul 30, 20195 citations

Relaxation Effects

WORLD SCIENTIFIC eBooksOct 1, 20080 citations

Memory Effects

Bassano Vacchini

Graduate texts in physicsJan 1, 20240 citations

Effects of disorder on high-temperature superconductors

Tai Kai Ng

The effect of disorder on high-temperature superconductors is studied using a phenomenologically modified scaling theory for disordered interacting fermions. It is found that the effect of disorder on high-temperature superconductors is very different from the effect on a normal metal because of the ``marginal''-Fermi-liquid effect. In particular, we found that the system always scales toward strong disorder if the ``marginal'' effect is strong enough. Correspondingly, the magnetic susceptibility goes to zero.The effect of disorder on high-temperature superconductors is studied using a phenomenologically modified scaling theory for disordered interacting fermions. It is found that the effect of disorder on high-temperature superconductors is very different from the effect on a normal metal because of the ``marginal''-Fermi-liquid effect. In particular, we found that the system always scales toward strong disorder if the ``marginal'' effect is strong enough. Correspondingly, the magnetic susceptibility goes to zero.

Physical review. B, Condensed matterMay 1, 19920 citations

Ensembles and Effects

Günther Ludwig

Springer eBooksJan 1, 19831 citation

Effects of off-diagonal disorder on a four-dimensional topological insulator

Xiang Liu, Xiao-Xia Yi, Zheng‐Rong Liu +2 more

While the effects of off-diagonal disorder have been extensively studied in low-dimensional topological systems, such research remains insufficient in four-dimensional (4D) topological systems. In this work, we investigate the effect of off-diagonal disorders on a 4D topological insulator. We find that off-diagonal disorder can induce a 4D topological Anderson insulator (TAI) phase. This differs from previous finding in two-dimensional topological insulators, where off-diagonal disorder fails to induce the TAI phase. Specifically, we consider 16 different configurations of disorder and identify two distinct types based on their effect on the system. Furthermore, using the self-consistent Born approximation, we elucidate the unique role of off-diagonal disorder in these phase transitions compared to the diagonal Anderson disorder.While the effects of off-diagonal disorder have been extensively studied in low-dimensional topological systems, such research remains insufficient in four-dimensional (4D) topological systems. In this work, we investigate the effect of off-diagonal disorders on a 4D topological insulator. We find that off-diagonal disorder can induce a 4D topological Anderson insulator (TAI) phase. This differs from previous finding in two-dimensional topological insulators, where off-diagonal disorder fails to induce the TAI phase. Specifically, we consider 16 different configurations of disorder and identify two distinct types based on their effect on the system. Furthermore, using the self-consistent Born approximation, we elucidate the unique role of off-diagonal disorder in these phase transitions compared to the diagonal Anderson disorder.

Journal of Physics Condensed MatterJul 21, 20260 citations

{T}_{c}

. Along with these hints at decrease in effective disorder, speckle correlations also suppress the superfluid gap and the gap formation temperature---effects normally associated with increasing disorder. We correlate these effects with the effective potential and the single-particle localization effects in the ground state.