We determine the ground-state energy and the effective dispersion law for a one-dimensional system of point bosons under zero boundary conditions. The ground-state energy is close to the value for a periodic system. But the dispersion law is essentially different from that for a periodic system, if the coupling is weak (weak interaction or high concentration) or intermediate. We propose also a new method for construction of the thermodynamics for a gas of point bosons. It turns out that the difference in the dispersion laws of systems with periodic and zero boundary conditions does not lead to a difference in the thermodynamic quantities. In addition, under zero boundary conditions, the microscopic sound velocity does not coincide with the macroscopic one. This means that either the method of determination of k in the dispersion law E(k) is unsuitable or the lowenergy excitations are not phonons.

We have studied the microstructure of a system of interacting Bose particles under zero boundary conditions and have found two possible orderings. One ordering is traditional and is char-The second one is new and is characterized by the same dispersion law, but with q = 2 −d , where d is the number of noncyclic coordinates. At a weak interaction, the groundstate energy is less for the new solution. The boundaries affect the bulk microstructure due to the difference of the topologies of closed and open systems. K e y w o r d s: Bose particles, Bogolyubov dispersion law, Bose liquid, Bose gas.

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Previously, a quantum "tidal" mechanism of polarization of the atoms of He-II was proposed, according to which, as a result of interatomic interaction, each atom of He-II acquires small fluctuating dipole and multipole moments, oriented chaotically on the average.In this work, we show that, in the presence of a temperature or density gradient in He-II, the originally chaotically oriented tidal dipole moments of the atoms become partially ordered, which results in volume polarization of He-II. It is found that the gravitational field of the Earth induces electric induction △ϕ ∼ 10 −7 V in He-II (for vessel dimensions of the order of 10 cm). We study also the connection of polarization and acceleration, and discuss a possible nature of the electric signal △ϕ ≈ k B △T /2e observed by A. S. Rybalko in experiments with second sound.

An attempt is made to explain the nature of the electric signals observed in helium II in a second-sound standing wave. It is shown on the basis of the general principles of quantum mechanics that as a result of interatomic interactions each helium atom acquires a small induced dipole moment dat, which pulsates in time and space. A directed flux of microscopic vortex rings is formed in a second-sound standing half-wave. This flux partially orders the chaotically oriented dipole moments of the atoms, which results in volume polarization of helium II. The observed potential difference ΔU≈kBΔT∕2e can be explained theoretically by assuming that each ring possesses a dipole moment dvr of the order of 10 times the average value of the modulus of the atomic moment, dvr∼10d¯at. Analysis taking account of the boundary conditions also shows that a different possible nature of the observed electric signal ΔU is also not ruled out: this signal is associated not with the properties of HeII but rather with a form of the thermal electromotive force.