arXiv subjects

O. Dutta

Publications and source records attributed to O. Dutta.

10 recordsLinked to original sources

arXiv2017

Solitons in one-dimensional lattices with a flat band

We investigate the spectral properties of a quasi-one-dimensional lattice in two possible dimerisation configurations. Both configurations are characterized by the same lattice topology and the identical spectra containing a flat band at zero energy. We find that one of the dimerised configuration has similar symmetry to a one-dimensional chain proposed by Su-Schrieffer-Heeger for studying solitons in conjugated polymers. Whereas, the other dimerised configuration only shows non-trivial topological properties in the presence of chiral-symmetry breaking adiabatic pumping.

cond-mat.mes-hall↗

arXiv2014

Emergent non-trivial lattices for topological insulators

Materials with non-trivial lattice geometries allow for the creation of exotic states of matter like topologically insulating states. Therefore searching for such materials is an important aspect of current research in solid-state physics. In the field of ultracold gases there are ongoing studies aiming to create non-trivial lattices using optical means. In this paper we study two species of fermions trapped in a square optical lattice and show how non-trivial lattices can emerge due to strong interaction between atoms. We theoretically investigate regimes of tunable parameters in which such self-assembly may take place and describe the necessary experimental conditions. Moreover we discuss the possibility of such emergent lattices hosting topologically insulating states.

cond-mat.quant-gas↗

arXiv2014

Many body population trapping in ultracold dipolar gases

A system of interacting dipoles is of paramount importance for understanding of many-body physics. The interaction between dipoles is {\it anisotropic} and {\it long-range}. While the former allows to observe rich effects due to different geometries of the system, long-range ($1/r^3$) interactions lead to strong correlations between dipoles and frustration. In effect, interacting dipoles in a lattice form a paradigmatic system with strong correlations and exotic properties with possible applications in quantum information technologies, and as quantum simulators of condensed matter physics, material science, etc. Notably, such a system is extremely difficult to model due to a proliferation of interaction induced multi-band excitations for sufficiently strong dipole-dipole interactions. In this article we develop a consistent theoretical model of interacting polar molecules in a lattice by applying the concepts and ideas of ionization theory which allows us to include highly excited Bloch bands. Additionally, by involving concepts from quantum optics (population trapping), we show that one can induce frustration and engineer exotic states, such as Majumdar-Ghosh state, or vector-chiral states in such a system.

cond-mat.quant-gas↗

arXiv2013

Nanoplasmonic planar traps - a tool for engineering p-wave interactions

Engineering strong p-wave interactions between fermions is one of the challenges in modern quantum physics. Such interactions are responsible for a plethora of fascinating quantum phenomena such as topological quantum liquids and exotic superconductors. In this letter we propose to combine recent developments of nanoplasmonics with the progress in realizing laser-induced gauge fields. Nanoplasmonics allows for strong confinement leading to a geometric resonance in the atom-atom scattering. In combination with the laser-coupling of the atomic states, this is shown to result in the desired interaction. We illustrate how this scheme can be used for the stabilization of strongly correlated fractional quantum Hall states in ultracold fermionic gases.

cond-mat.quant-gas↗

arXiv2012

Orbital physics of polar Fermi molecules

We study a system of polar dipolar fermions in a two-dimensional optical lattice and show that multi-band Fermi-Hubbard model is necessary to discuss such system. By taking into account both on-site, and long-range interactions between different bands, as well as occupation-dependent inter- and intra-band tunneling, we predict appearance of novel phases in the strongly-interacting limit.

cond-mat.quant-gas↗

arXiv2010

Unconventional superfluidity of fermions in Bose-Fermi mixtures

We examine two dimensional mixture of single-component fermions and dipolar bosons. We calculate the self-enregies of the fermions in the normal state and the Cooper pair channel by including first order vertex correction to derive a modified Eliashberg equation. We predict appearance of superfluids with various non-standard pairing symmetries at experimentally feasible transition temperatures within the strong-coupling limit of the Eliashberg equation. Excitations in these superfluids are anyonic and follow non-Abelian statistics.

cond-mat.quant-gas↗

arXiv2009

Unconventional superfluidity in Bose-Fermi Mixtures

Pairing between fermions that attract each other, reveal itself to the macroscopic world in the form of superfluidity. Since the discovery of fermionic superfluidity, intense search has been going on to find various unconventional forms of fermion pairing as well as to increase the transition temperature. Here, we show that a two dimensional mixture of single-component fermions and dipolar bosons allows to reach experimentally feasible superfluid transition temperatures for non-standard pairing symmetries. Excitations in these superfluids are anyonic and their statistics depends on the order of their permutations, i.e is non-Abelian. Our results provide for the first time an example of a highly tunable system which exhibits various kind of pairing symmetry and high transition temperature. Additionally, they provide a playground to observe anyonic excitations and their braiding properties.

cond-mat.quant-gas↗

arXiv2008

Stability of the density-wave state of a dipolar condensate in a pancake trap

We study a dipolar boson-fermion mixture in a pancake geometry at absolute zero temperature, generalizing our previous work on the stability of polar condensates and the formation of a density-wave state in cylindrical traps. After examining the dependence of the polar condensate stability on the strength of the fermion-induced interaction, we determine the transition point from a ground-state Gaussian to a hexagonal density-wave state. We use a variational principle to analyze the stability properties of those density-wave state.

cond-mat.other↗

arXiv2008

Coupling nanomechanical cantilevers to dipolar molecules

We investigate the coupling of a nanomechanical oscillator in the quantum regime with molecular (electric) dipoles. We find theoretically that the cantilever can produce single-mode squeezing of the center-of-mass motion of an isolated trapped molecule and two-mode squeezing of the phonons of an array of molecules. This work opens up the possibility of manipulating dipolar crystals, which have been recently proposed as quantum memory, and more generally, is indicative of the promise of nanoscale cantilevers for the quantum detection and control of atomic and molecular systems.

quant-ph↗

arXiv2007

Ground-state structure and stability of dipolar condensates in anisotropic traps

We study the Hartree ground state of a dipolar condensate of atoms or molecules in an three-dimensional anisotropic geometry and at T=0. We determine the stability of the condensate as a function of the aspect ratios of the trap frequencies and of the dipolar strength. We find numerically a rich phase space structure characterized by various structures of the ground-state density profile.

cond-mat.other↗