Nonlocal bunching of composite bosons

Abstract

It was suggested that two entangled fermions can behave like a single boson and that the bosonic quality is proportional to the degree of entanglement between the two particles. The relation between bosonic quality and entanglement is quite natural if one takes into account the fact that entanglement appears in bound states of interacting systems. However, entanglement can still be present in spatially separated subsystems that do not interact anymore. These systems are often a subject of studies on quantum nonlocality and foundations of quantum physics. Here, we ask whether an entangled spatially separated fermionic pair can exhibit bosonic properties. We show that in certain conditions the answer to this question can be positive. In particular, we propose a nonlocal bunching scenario in which two such pairs form an analogue of a two-partite bosonic Fock state.

Assembly of 2N entangled fermions into multipartite composite bosons

“…Nevertheless, although entanglement cannot be created without interactions, in principle it does not require interactions to last, once it is created. This allows to study the concept of composite particles that are bound solely by entanglement [14,15].…”

“…More precisely, the more entangled two fermions are, the more bosonic they behave [1,2]. This result established a new field of research, the quantum information oriented studies on composite bosons [3][4][5][6][7][8][9][10][11][12][13][14][15]. Up to now scientists focussed on composite bosons made of two elementary components, whose quality can be quantified by bipartite entanglement.…”

Dynamical stability of composite quantum particles: When entanglement is enough and when interaction is needed

“…In our previous work [29], we argued that the evolution of a composite quantum particle from a localized state to a delocalized one requires production of entanglement. More precisely, consider a transformation of the form c † x0 → x α x c † x , where c † x is a particle creation operator at position x and x |α x | 2 = 1.…”