Boson-like behaviour of pairs of fermions (I)

Aleksej Nikolaevich Storozhenko

Jonte R. Hance

Abstract In this short topical review, we look at something typically considered trivial, but not given formally elsewhere—the behaviour of first multiple fermions, then multiple bosons, in a beamsplitter. Extending from this, we then describe the behaviour of multiple fermions and multiple bosons in Mach–Zehnder interferometers. We hope that by showing how to go from mathematically simple but unintuitive quantum field theory to a phenomenological description, this review will help both researchers and students build a stronger intuition for the behaviour of quantum particles.

V. A. Yatsun

B. Sørensen

Grzegorz Pawłowski, S. Robaszkiewicz, R. Micnas

The influence of randomness of local pair site energies on superconducting properties of a system of coexisting local pairs and itinerant electrons described by the (hard-core) boson-fermion model is analyzed within variational BCS Hartree-Fock approach.Assuming the rectangular distribution function of the random potential the phase diagrams, critical temperatures, and the chemical potential behaviours are determined.

Zakarya Lasmar

On the role of entanglement in the formation and stability of composite bosons by mgr.Zakarya Lasmar Composite bosons are many-body systems made of many elementary bosons, or an even number of elementary fermions.Recently, it was suggested that quantum entanglement can be understood as the origin of the bosonic character of the simplest systems of this type (bipartite composite bosons).This idea motivated a new direction of research: quantum information oriented study of composite particles.In the present work, the role of entanglement in the formation and dynamics of composite bosons is studied.We show that, in some special situations, two entangled fermions can exhibit bosonic behaviour while being specially separated.We propose a nonlocal scheme that leads two pairs of entangled fermions to form an analogue of a two-partite bosonic Fock state.Also, we show that in some situations entanglement can provide stability for a composite particle.In this case, the interaction-free dynamics of an entangled bipartite system appear to mimic the behaviour of two interacting particles.In addition, we discuss the possible reasons that can limit the influence of entanglement on the behaviour of composite particles.The no-signalling condition seems to play a crucial role, which suggests that interactions in some situations become necessary.Regarding the formation of composite bosons, I present an entanglement-based method to study the bosonic quality of fermionic multipartite systems.Using this method, I examine the bosonic quality of the ground state of the extended one-dimensional Hubbard model while tuning the strength of interactions.vii