We consider a bidimensional system of few identical bosons trapped in a harmonic well that interact through a two-body gaussian potential. We discuss the ground state energy using a mean-field approximation and introducing pair correlations. To solve the many-body problem we used Monte Carlo techniques: Variational and Diffusion Monte Carlo. We find that two-body correlations lower significantl...

The ground states of all even-even nuclei have angular momentum, I, equal to zero, I = 0, and positive parity, π = +. This feature was believed to be a consequence of the attractive short-range interactions between nucleons. However, in the presence of two-body random interactions, the predominance of I = 0 ground states (0 g.s.) was found to be robust both for bosons and for an even number of ...

We study a Bose-Einstein condensate with attractive interactions in a one-dimensional ring and show that the ground state is well described by the superposition of bright solitons. A position measurement of some atoms gives rise to the state reduction of the soliton position, which increases the condensate fraction. The bunched many-body ground state is well approximated by a simple variational...

We present an approach to dynamic decoherence control of finite-temperature Bose-Einstein condensates in a double-well potential. Due to the many-body interactions the standard “echo” control method becomes less effective. The approach described here takes advantage of the interaction-induced change of the spectrum, to obtain the optimal rate of flips of the relative phase between maximally dis...

The quantum 2-component DS1 system in two dimensions has been reduced to two 2-component many-body problems both in one dimension by an analogue of the method of separation of variables. The solutions to 2 dimensional problem under consideration can be constructed from the resulting problem in one dimensions. For latters with the δ-function interactions and being solved by the Bethe ansatz, we ...

The interplay of electron-electron interactions and spin-orbit coupling leads to a new contribution to the homogeneous optical conductivity of the electron liquid. The latter is known to be insensitive to many-body effects for a conventional electron system with parabolic dispersion. The parabolic spectrum has its origin in the Galilean invariance which is broken by spin-orbit coupling. This op...

I will review recent progress in our understanding of the nuclear force. In the course of the 1990’s, so-called high-precision, charge-dependent nucleon-nucleon potentials have been constructed which are, essentially, phenomenological models. These potentials are now commonly used as input for exact few-body calculations and microscopic nuclear many-body theory. I will critically analyses those...

We consider long-range interactions between two alkali-metal atoms in their respective ground states. We extend the previous relativistic many-body calculations of C6 dispersion coefficients @Phys. Rev. Lett. 82, 3589 ~1999!# to higher-multipole coefficients C8 and C10 . Special attention is paid to usually omitted contribution of core-excited states. We calculate this contribution within relat...