arXiv subjects

Arjo Dasgupta

Publications and source records attributed to Arjo Dasgupta.

4 recordsLinked to original sources

arXiv2026

Anyon condensates of dipoles in triangular ladders

Hard-core dipoles in triangular ladders are an excellent platform for the study of the interplay between frustration and long-range interactions, well described by a modified version of the celebrated $J_1$--$J_2$ model. Interestingly, as shown in [Phys. Rev. Lett. 109, 227203 (2012)], such a model presents, for particular exactly-solvable conditions, a peculiar phase known as an anyon condensate. We show that balanced anyon condensates are robust against deviations from the exactly-solvable conditions, and discuss the requirements for dipolar orientation and ladder geometry, to realize anyon condensates of dipoles in triangular ladders, whose anyonic nature may be easily revealed by time-of-flight measurements. Moreover, the ground-state physics in the vicinity of the exactly-solvable point is very rich, including a phase transition from anyon condensates into chiral superfluids, and self-bound Mott insulators, bond-order insulators, and chiral liquids.

cond-mat.quant-gas↗

arXiv2025

Chiral phases and dynamics of dipoles in triangular optical ladders

Dipoles in triangular optical ladders constitute a flexible platform for the study of the interplay between geometric frustration and long-range anisotropic interactions, and in particular for the observation of the spontaneous onset of chirality. Frustration magnifies the effect of the dipolar interactions in itinerant polarized dipolar bosons. As a result, the dipole-induced transition between a chiral superfluid and a non-chiral two-component superfluid may be observed for current state-of-the-art temperatures even for the weak inter-site interaction characterizing magnetic atoms in standard optical lattices. On the other hand, pinned spin-$1/2$ dipoles, which we discuss in the context of polar molecules in two rotational states, realize frustrated dipolar XXZ spin models. By controlling the external electric field strength and orientation, these systems can explore a rich ground-state landscape including chiral and nematic phases, as well as intriguing chiral dynamics.

cond-mat.quant-gas↗

arXiv2024

Gapless Edge-Modes and Topology in the Qi-Wu-Zhang Model: A Real-Space Analysis

The topological phase transition in the Qi-Wu-Zhang model is studied using a real-space approach. An effective Hamiltonian for the topologically protected edge-modes in a finite-size system is developed. The topological phase transition is understood in terms of a global perturbation to the system which lifts the degeneracy of the edge-modes. The effective Hamiltonian method is also applied to a one-dimensional system with spatially varying hopping strengths to understand the impact of disorder on the edge-modes.

cond-mat.mes-hall↗

arXiv2023

The Anatomy of a Topological Phase Transition in a 2D Chern Insulator

The onset of the topological phase transition in a two-dimensional model for a Chern Insulator, namely the Qi-Wu-Zhang(QWZ) model, is illustrated, with particular emphasis on the appearance of chiral edge-modes. The edge-modes are studied by analysing the dynamics of the edge-states in an equivalent model for a one-dimensional charge pump, using a technique known as dimensional extension. A further real-space analysis allows us to explain the onset of the topological phase transition in terms of time-reversal symmetry breaking and to quantitatively study the localisation of the edge-modes.

cond-mat.mes-hall↗