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MajuLab’s team article as Editor’s Choice at Phys. Rev. A.

by MajuLab editor - published on , updated on

MajuLab's team article as Editor's Choice at Phys. Rev. A.

Matteo Rizzi, Christian Miniatura, Anna Minguzzi, and Patrizia Vignolo Phys. Rev. A 98, 043607 – Published 4 October 2018

The relation between 2-body and many-body physics is often an important point for the comprehension and the description of strongly-correlated quantum systems.

A celebrated example is provided by homogeneous 1D interacting systems solvable by the Bethe Ansatz, such as bosons and fermions with contact interactions. In such a case, the N-body solution can be exactly expressed as a function of a product of two-body scattering contributions.

A crucial observable for a 1D system of N particles with contact interactions of strength g is the so-called Tan’s contact parameter C(N,g), characterizing the asymptotic behavior of the 1-body momentum distribution n(k) which decays algebraically like C(N,g)/k^4 at large momenta.

The contact parameter is also determined by the probability density of finding 2 particles at a vanishing distance and embeds information on the interaction energy and the density-density correlation function. It is a univocal measure of the wavefunction symmetry of fermionic and/or bosonic mixtures.

In our paper, we have shown that the contact parameter can be simply and accurately obtained from an appropriate rescaling of the 2-body contact parameter. Indeed, almost all the dependence of the contact on the number of particles can be embedded in the contact at infinite interactions for any number of particles.

Our results seem to be general and not to depend on the particle statistics.
They thus show the fundamental role of the contact, likely due to its local 2-body correlation nature, and suggest a change of paradigm in the study of interacting quantum systems, giving a more fundamental role to the contact parameter than to the energy.

Our work constitutes an important step forward in understanding the effects of correlations and interactions in 1D interacting boson and fermion mixtures.

See online : Editor’s Choice à Phys. Rev. A