Starting from classic work of Feynman on the $λ$-point of liquid Helium, we show that his idea of universal action per particle at the BEC transition point is much more robust that it was known before. Using a simple "moving string model" for supercurrent and calculating the action, both semiclassically and numerically, we show that the critical action is the same for noninteracting and strongly interacting systems such as liquid ${}^4$He. Inversely, one can obtain accurate dependence of critical temperature on density: one important consequence is that high density (solid) He cannot be a BEC state of He atoms, with upper density accurately matching the observations. We then use this model for the deconfinement phase transition of QCD-like gauge theories, treated as BEC of (color)magnetic monopoles. We start with Feynman-like approach without interaction, estimating the monopole mass at $T_c$. Then we include monopole's Coulomb repulsion, and formulate a relation between the mass, density and coupling which should be fulfilled at the deconfinement point. We end up proposing various ways to test on the lattice whether it is indeed the BEC point for monopoles.
Under the assumption of Abelian dominance in QCD, we show that either color charge or chirality of quark is not conserved, when the low energy massless quark collides with QCD monopole. Because the color charge is conserved in reality, the chirality is not conserved. We show by using chiral anomaly that chiral non symmetric quark pair production takes place when a classical color charge is putted in a vacuum with monopole condensation, while chiral symmetric pair production takes place in a vacuum with no monopole condensation. Our results indicate that the chiral symmetry is broken by the mon…
In this paper we improve the existing order parameter for monopole condensation in gauge theory vacuum, making it gauge-invariant from scratch and free of the spurious infrared problems which plagued the old one. Computing the new parameter on the lattice will unambiguously detect weather dual superconductivity is the mechanism for color confinement. As a byproduct we relate confinement to the existence of a finite correlation length in the gauge-invariant correlator of chromo-electric field strengths.
Thermal monopoles, identified after Abelian projection as magnetic currents wrapping non-trivially around the thermal circle, are studied in $N_f = 2+1$ QCD at the physical point. The distribution in the number of wrappings, which in pure gauge theories points to a condensation temperature coinciding with deconfinement, points in this case to around 275 MeV, almost twice the QCD crossover temperature $T_c$; similar indications emerge looking for the formation of a percolating current cluster. The possible relation with other non-perturbative phenomena observed above $T_c$ is discussed.
We study Bose-Einstein condensation and formation of Bose stars in the virialized dark matter halos/miniclusters by universal gravitational interactions. We prove that this phenomenon does occur and it is described by kinetic equation. We give expression for the condensation time. Our results suggest that Bose stars may form kinetically in the mainstream dark matter models such as invisible QCD axions and Fuzzy Dark Matter.
We study the Bose condensation of scalar dark matter in the presence of both gravitational and self-interactions. Axions and other scalar dark matter in gravitationally bound miniclusters or dark matter halos are expected to condense into Bose-Einstein condensates called Bose stars. This process has been shown to occur through attractive self-interactions of the axion-like particles or through the field's self gravitation. We show that in the high-occupancy regime of scalar dark matter, the Boltzmann collision integral does not describe either gravitaitonal or self-interactions, and derive kin…
