Non-Relativistic Bose-Einstein Condensates, Kaon droplets, and Q- Balls

We note the similarity between BEC (Bose-Einstein Condensates) formed of atoms between which we have long-range attraction (and shorter-range repulsions) and the field theoretic "Q balls". This allows us in particular to address the stability of various putative particle physics Q balls made of non-relativistic bosons using variational methods of many-body physics

The BCS - BEC Crossover In Arbitrary Dimensions

Cold atom traps and certain neutron star layers may contain fermions with separation much larger than the range of pair-wise potentials yet much shorter than the scattering length. Such systems can display {\em universal} characteristics independent of the details of the short range interactions. In particular, the energy per particle is a fraction $\xi$ of the Fermi energy of the free Fermion system. Our main result is that for space dimensions D smaller than two and larger than four a specific extension of this problem readily yields $\xi=1$ for all $D \le 2$ whereas $\xi$ is rigorously non-positive (and potentially vanishing) for all $D \ge 4$. We discuss the D=3 case. A particular unjustified recipe suggests $\xi=1/2$ in D=3.Comment: 9 pages, 1 figur

Tests of CPT

The ongoing experimental efforts in the high energy and high precision communities keep providing evidence for CPT, a fundamental symmetry holding in any local Lorentz invariant theory. We suggest possible interconnections between different CPT violating parameters. Specifically, the very precise test of CPT in the $K^0-\bar K^0$ system suggests--though definitely does not imply--that CPT violations in other observable parameters (mass, width, charge, magnetic moments, etc.) are much smaller than the directly measured bounds.Comment: 7 pages, 1 figur

A Novel Approach to Complex Problems

A novel approach to complex problems has been previously applied to graph classification and the graph equivalence problem. Here we consider its applications to a wide set of NP complete problems, namely, those of finding a subgraph g inside a graph G.Comment: 9 page

From Higgs to pions and Back -- the Unbearable Lightness of a Composite Scalar Boson at 125 GeV in Purely Vectorial Theories

We argue that the $125 GeV$ "Higgs" particle is unlikely to arise as a fermion- antifermion composite if the underlying dynamics is a vectorial gauge theory. The reason is that the lightest scalar in such theories is heavier than the lightest pseudo-scalar with the mass difference being fixed by the scale of the theory. LHC searches suggest that the scale of any new physics, including that of a putative new theory dynamically generating the 125 GeV "Higgs" particle, is relatively high $\sim{(1/2TeV-1TeV)}$. Also the LHC analysis suggests that it is {\it scalar} namely $J^P = 0^+$ rather than pseudo-scalar. Thus it is unlikely that the "Higgs" could arise as a composite in such theories- though it will arise in special cases when the underlying binding gauge group is real as a fermion-fermion bound state. The direct considerations of the various two point functions in the large $N_c$ limit presented below- suggest that massless pseudo-scalars, but not any other anomalously light meson, arise as composites of massless fermions say the massless u and $\bar{d}$ quarks in QCD. These massless pions manifest the spontaneous breaking of the global axial symmetry in QCD with the pions being (pseudo) Nambu Goldstone Bosons. This offers a different insight into SXSB in QCD and most other confining non-abelian gauge vectorial gauge theory. Specifically we consider the euclidean two point functions $F_I|x-y|$ for asymptotic $|x-y|$ expressed as a sum over fermionic paths. We conjecture that for the pseudo-scalar two point function - and for that case only- self retracing paths and closely related paths make in this limit a positive, coherent and dominant contribution, a contribution which evades the generic asymptotic exponential fall-off and allows the lightest pseudoscalars to be massless. The same arguments imply that the scalars are very massive

Are Bulk Axions in Models with Extra, Large, Compact Dimensions Observable?

The high degeneracy of KK modes in models which have bulk axions moving in some extra, compact dimensions which are larger than O (Angstrom)strongly tightens the supernova upper bounds on the axion photon coupling making axions practically unobservable. Conversely, discovering axions directly or indirectly will exclude such models. These drastic conclusions are avoided if the supernova and bounds from solar axion searches are relaxed.Comment: 7 pages; cross-reference with Astrophysic

Early inflation induced gravity waves can restrict Astro-Particle physics

In this paper, we discuss limits on various astro-particle scenarios if the scale \textit{and} the reheat temperature of the last relevant inflation were very high. While the observed "B" like pattern of polarizations of the CMB suggest a very high ($\ge 10^{16}\ GeV$) scale of a primordial (which motivated this work initially) and may reflect effects of dust, we believe that addressing these issues is nonetheless very useful. We recall the potential difficulties with various topological defects - monopoles, strings and domain walls generated at the SSB (spontaneous symmetry breaking) of various gauge symmetries. The main part of the paper is devoted to discussing difficulties with long-lived heavy particles, which could be dark matter but cannot efficiently annihilate to the required residual density because of basic S-Matrix unitarity/analyticity limits. We indicate in simple terms yet in some detail how the WIMP miracle occurs at $M(X)\sim{TeV}$ and how the axiomatic upper bound presently updated to $M(X) \le{110 TeV}$ was originally derived by Greist and Kamionokowski. We also argue that generically we expect the stronger $M(X)\le{20\ GeV}$ bound to hold. We then elaborate on the pure particle physics approaches aiming to enhance the annihilation and evade the bounds. We find that the only and in fact very satisfactory way of doing this requires endowing the particles with gauge interactions with a confinement scale lower than $M(X)$. We also comment on models with light $O(KeV)$ dark matter, which was supposed to be frozen in via out-of equilibrium processes so as to have the right relic densities pointing out that in many such cases \textit{very} low reheat temperatures are indeed required and speculate on the large desert scenario of particle physics. Most of what we discuss is not new but was not presented in a coherent fashion

Some Comments on Possible Preferred Directions for the SETI Search

The search for extraterrestrial intelligence by looking for signals from advanced technological civilizations has been ongoing for some decades. We suggest that it could possibly be made more efficient by focusing on stars from which the solar system can be observed via mini-eclipsings of the Sun by transiting planets.Comment: 12 page

Dark Matter Tomography

We consider Wimp annihilations into monochromatic and continuous $\gamma$'s and the angular distribution of the resulting gammas. We discuss how the WIMP density profile can be reconstructed from the angular dependence of the photon flux.Comment: 6 pages, 1 figur

Is the Froissart bound relevant for the total pp cross section at s=(14 TeV)^2?

The Froissart bound limmits the asymptotic s->infinity behavior of crossections by (\pi/t_0) ln ^2 (s/{(s_0)} where t_0 is the lightest exchanged particle, or more generally the nearest ssingularity, in the t channel. We suggest that in comparing this bound with data at energies less than those of LHC, gluebaall masses raather than the small pion mass should be used for (t_0)^{1/2}.Comment: 17 Pages, 1 Figur