Two- and Three-Particle Correlations in q,p-Bose Gas Model

I. V. Barashenkov, Kholmirzo T. Kholmurodov

Vladmir G. Makhankov, Kholmirzo T. Kholmurodov

The problem of Bose-condensate stability is studied in the model with two-particle attraction and three-particle repulsion. Two channels of condensate decomposition are established, one of which is associated with an excitation of one bubble and the other with bubble gas in the condensate. Calculations show that the gas channel of decomposition is more advantageous from the energy point of view since it takes place at lower temperatures in comparison with the one-soliton channel.

N. M. Bogoliubov

Paul Berdahl

The two- and three-particle distribution functions of the weakly interacting Bose gas in its ground state are studied via the calculation of their Fourier transforms. The form obtained for the three-particle distribution function shows that the familiar convolution approximation is not correct even in the lowest nontrivial order of perturbation theory. For the special case of the charged Bose gas at high density, the two-particle distribution function is obtained to second order in the expansion parameter ${r}_{s}^{\frac{3}{4}}$, a result which disagrees with a recent calculation. The discrepancy is traced to a use of the convolution approximation for the three-particle distribution function. Finally, Landau's theory of quantum hydrodynamics is employed to relate the long-range part of the three-particle distribution function to the Gr\"uneisen constant. These results emphasize the need to treat properly the dynamic three-particle correlations in any quantitative theory of liquid helium.

David Clément

Fletcher, RJ, Raphael Lopes, Jay Man +4 more

In many-body systems governed by pairwise contact interactions, a wide range of observables is linked by a single parameter, the two-body contact, which quantifies two-particle correlations. This profound insight has transformed our understanding of strongly interacting Fermi gases. Using Ramsey interferometry, we studied coherent evolution of the resonantly interacting Bose gas, and we show here that it cannot be explained by only pairwise correlations. Our experiments reveal the crucial role of three-body correlations arising from Efimov physics and provide a direct measurement of the associated three-body contact.