Question Condensates

[Harry Costas]

Science does not break down.
Where did you get t=0. ?

 

[Harry Costas]

Condensate research is one of the most important fields to date.

[Submitted on 22 Jan 2025]

Magnetic phase diagram of cuprates and universal scaling laws​

Yves Noat, Alain Mauger, William Sacks

In this article we consider the magnetic field phase diagram of hole-doped high-Tc cuprates, which has been given much less attention than the temperature diagram. In the framework of the {\it pairon model}, we show that the two characteristic energies, the pair binding energy (the gap Δp) and the condensation energy (βc) resulting from pair correlations, give rise to two major magnetic fields, the upper critical field Bc2 and a second field, Bpg, associated with the pseudogap (PG). The latter implies a second length scale in addition to the coherence length, characteristic of incoherent pairs. Universal scaling laws for both Bc2 and Bpg are derived: Bc2 scales with the critical temperature, Bc2/Tc≃1.65 T/K, in agreement with many experiments, and Bpg has a similar scaling with respect to T∗. Finally, Fermi arcs centered on the nodal directions are predicted to appear as a function of magnetic field, an effect testable experimentally.

 

[Harry Costas]

For those who want to understand more and more, then keep on it.

[Submitted on 10 Feb 2025 (v1), last revised 16 Feb 2025 (this version, v2)]

Fermion mediated pairing in the Ruderman-Kittel-Kasuya-Yosida to Efimov transition regime​

Geyue Cai, Henry Ando, Sarah McCusker, Cheng Chin

The Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction and Efimov physics are two distinct quantum phenomena in condensed matter and nuclear physics, respectively. The RKKY interaction describes correlations between impurities mediated by an electron gas, while Efimov physics describes universal bound states of three particles with resonant interactions. Recently, both effects have been observed in Bose-Fermi mixtures in the weak and resonant interaction regimes, respectively. Intriguing conjectures exist to elucidate how the two phenomena meet in the transition regime where the mixture is strongly interacting. In this work, we explore the RKKY-Efimov transition in a mixture of bosonic Cs-133 and fermionic Li-6 near a tunable interspecies Feshbach resonance. From dispersion and relaxation measurements, we find that the transition is highlighted by a fermion-mediated scattering resonance between Cs atoms and a weaker resonance on Li atoms. These resonances represent reactive scattering of Cs and Li atoms in the many-body regime, which reduces to an Efimov resonance in the thermal gas regime. Our observation demonstrates the intriguing interplay of two-, three-, and many-body physics in an Bose-Fermi mixture that connects condensed matter physics, nuclear physics and quantum many-body chemistry.

 

[Harry Costas]

The research into Transient Phases of condensates has enabled scientists to understand further the power of condensates that can form Vortex (Jets), and lead to understanding the formation of stars and different forms of galaxies.

See below (If quark stars are a transition state between neutron stars and black holes, then black holes ought to be equivalent to boson stars, after all the residual quark material has formed a Bose-Einstein condensate of strange mesons.)

[Submitted on 10 Feb 2025 (v1), last revised 1 Mar 2025 (this version, v2)]

WilloWISPs: A New Dark Growth Channel for Black Holes Suggests a Full-Spectrum Hierarchical MACHO Mass Function for Dark Matter​

Zachary R. Smith, Neil F. Comins

Evidence of neutron stars with deconfined quark-matter cores suggest a new pathway for the evolution of black holes. New theories about the cores of neutron stars support the idea that quarkonium is likely to grow there as the neutron star ages. Surveys of stellar remnants have shown that there is no major mass gap between neutron stars and black holes. Black holes, specifically primordial ones (PBHs), have been suggested as an explanation for dark matter before. However, the way that very large black holes can form in the lifetime of the visible universe has only recently been explained with a promising solution to The Final Parsec Problem. If neutron stars can become exotic stars or black holes surrounded by axions, then they may allow Intermediate-Mass Black Holes (IMBH) and Supermassive Black Holes (SMBH) to form quickly enough via coalescence. We find that a hierarchical clustering of Massive and Compact Halo Objects (MACHOs) with axion-dominated mini-halos can help to explain all of the missing dark matter. The model presented here suggests that this type of MACHO is likely equivalent to black holes above an unknown critical mass, which is less than ~1 M⊙, and that they ought to be quark stars below this mass. If quark stars are a transition state between neutron stars and black holes, then black holes ought to be equivalent to boson stars, after all the residual quark material has formed a Bose-Einstein condensate of strange mesons.

 

[Harry Costas]

Getting interesting

[Submitted on 12 Feb 2025]

Flipped Rotating Axion Non-minimally Coupled to Gravity: Baryogenesis and Dark Matter​

Chao Chen, Suruj Jyoti Das, Konstantinos Dimopoulos, Anish Ghoshal

We demonstrate that the co-genesis of baryon asymmetry and dark matter can be achieved through the rotation of an axion-like particle, driven by a flip in the vacuum manifold's direction at the end of inflation. This can occur if the axion has a periodic non-minimal coupling to gravity, while preserving the discrete shift symmetry. In non-oscillating inflation models, after inflation there is typically a period of kination (with w=1). In this case, it is shown that the vacuum manifold of the axion is flipped and the axion begins rotating in field space, because it can slide across the decreasing potential barrier as in Ricci reheating. Such a rotating axion can generate the baryon asymmetry of the Universe through spontaneous baryogenesis, while at later epochs it can oscillate as dark matter. The period of kination makes the primordial gravitational waves (GW) generated during inflation sharply blue-tilted which constrains the parameter space due to GW overproduction, while being testable by next generation CMB experiments. As a concrete example, we show that such a cogenesis of baryon asymmetry and dark matter can be realized for the axion as the Majoron in the Type-I seesaw setup, predicting mass ranges for the Majoron below sub eVs, with right-handed neutrino mass above O(108) GeV. We also show that in order to avoid fragmentation of the axion condensate during the rotation, we require the non-minimal coupling \mbox{ξ∼(f/mP)2} or somewhat larger, where f is the axion decay constant.

 

[Harry Costas]

Kaon matter is Two Quarks. Can be compacted much more than Neutron matter.
Knowing that 3 Quarks make up Neutrons and Protons.

[Submitted on 15 Feb 2025 (v1), last revised 19 Feb 2025 (this version, v2)]

Chiral Symmetry in Dense Matter with Meson Condensation​

Takumi Muto, Toshiki Maruyama, Toshitaka Tatsumi

Kaon condensation in hyperon-mixed matter [(Y+K) phase], which may be realized in neutron stars, is discussed on the basis of chiral symmetry. With the use of the effective chiral Lagrangian for kaon--baryon and kaon--kaon interactions; coupled with the relativistic mean field theory and universal three-baryon repulsive interaction, we clarify the effects of the s-wave kaon--baryon scalar interaction simulated by the kaon--baryon sigma terms and vector interaction (Tomozawa--Weinberg term) on kaon properties in hyperon-mixed matter, the onset density of kaon condensation, and the equation of state with the (Y+K) phase. In particular, the quark condensates in the (Y+K) phase are obtained, and their relevance to chiral symmetry restoration is discussed.

 

[Harry Costas]

The more we research the more we learn.

[Submitted on 3 Mar 2025]

Reheating after Axion Inflation​

Tomohiro Fujita, Kyohei Mukaida, Tenta Tsuji

We investigate the reheating process in an axion inflation model where the inflaton couples to non-Abelian gauge fields via the Chern-Simons coupling. The Chern-Simons coupling leads to the efficient production of gauge fields via a tachyonic instability during inflation, whose implications have been actively studied in the literatures. Moreover, it has been recently pointed out that the produced gauge fields can be even thermalized during inflation, leading to warm inflation. Apparently, these findings seem to imply that the reheating is completed immediately after inflation because the tachyonic instability or the thermal friction induced by the Chern-Simons coupling cause the inflaton condensate to decay rapidly. Contrary to this naive expectation, however, we show that, in most of the parameter space, either the inflaton condensate, the inflaton particles, or the glueballs once dominate the Universe and their perturbative decay completes the reheating.