119341368
A Schematic model for rho - a(1) mixing at finite density and in-medium effective Lagrangian
Based on schematic two-level models extended to a{sub 1}-meson degrees of freedom, we investigate possible mechanisms of chiral restoration in the vector-axial-vector channels in cold nuclear matter. In the first part of this article we employ the massive Yang-Mills framework to construct an effective chiral Lagrangian based on low-energy mesonic modes at finite density. The latter are identified through nuclear collective excitations of ''meson''-sobar type such as {pi}{r_reversible}[{delta}(1232)N{sup -1}]{identical_to}{pi}, {rho}{r_reversible}[N{sup *}(1520)N{sup -1}]{identical_to}{rho}, etc. In a mean-field type treatment the in-medium gauge coupling g, the (axial-)vector meson masses and f{sub {pi}} are found to decrease with density indicating the approach towards chiral restoration in the language of in-medium effective fields. In the second part of our analysis we evaluate the (first) in-medium Weinberg sum rule which relates vector and axial-vector correlators to the pion decay constant. Using in-medium {rho}/a{sub 1} spectral functions (computed in the two-level model) also leads to a substantial reduction of the pion decay constant with increasing density. (c) 2000 The American Physical Society.
3194304
Kaon Condensation and Enforced Charge Neutrality of the Color-Flavor Locked Phase
We investigate the influence of charged kaon condensation in hadronic sector on the formation of the electron-free charge neutral quark matter of equipartition of three light flavors, i.e., a phenomenon called ``enforced electrical neutrality" of the color-flavor locked (CFL) phase. We employ the chiral quark model which is assumed to be applicable, "bottom-up," toward chiral restoration while accessible to kaon condensation in the hadronic sector. Approaching "bottom-up" the high density regime is more appropriate in addressing the properties of compact stars than approaching "top-down" from asymptotic QCD. It turns out that the presence of hadronic kaon condensation makes the electron-free charge-neutral CFL phase energetically more favorable with a relatively small color-superconducting gap $\Delta_0\sim 20$ MeV compared to $\Delta_0\sim 70$ MeV required in the absence of such kaon condensation.
5924990
BARYON DENSITY AND THE DILATED CHIRAL QUARK MODEL
We calculate perturbatively the effect of density on hadronic properties using the chiral quark model implemented by the QCD trace anomaly to see the possibility of constructing a Lorentz-invariant Lagrangian at finite density. We calculate the density-dependent masses of the constituent quark, the scalar field, and the pion in one-loop order using the technique of thermofield dynamics. In the chiral limit, the pion remains massless at finite density. It is found that the tadpole-type corrections lead to decreasing masses with increasing baryon density, while the radiative corrections induce Lorentz-symmetry-breaking terms. We found in the large N{sub c} limit with large scalar mass that the tadpoles dominate and the mean-field approximation is reliable, giving rise to a Lorentz-invariant Lagrangian with masses decreasing as the baryon density increases. {copyright} {ital 1997} {ital The American Physical Society}
14364429
Can you do quantum mechanics without Einstein
The present form of quantum mechanics is based on the Copenhagen school of interpretation. Einstein did not belong to the Copenhagen school, because he did not believe in probabilistic interpretation of fundamental physical laws. This is the reason why we are still debating whether there is a more deterministic theory. One cause of this separation between Einstein and the Copenhagen school could have been that the Copenhagen physicists thoroughly ignored Einstein’s main concern: the principle of relativity. Paul A. M. Dirac was the first one to realize this problem. Indeed, from 1927 to 1963, Paul A. M. Dirac published at least four papers to study the problem of making the uncertainty relation consistent with Einstein’s Lorentz covariance. It is interesting to combine those papers by Dirac to make the uncertainty relation consistent with relativity. It is shown that the mathematics of two coupled oscillators enables us to carry out this job. We are then led to the question of whether the concept of localized probability distribution is consistent with Lorentz covariance.
118380480
Majorana zero modes in semiconductor nanowires in contact with higher- T c superconductors
We analyze the prospects for stabilizing Majorana zero modes in semiconductor nanowires that are proximity coupled to higher-temperature superconductors. We begin with the case of iron pnictides which, though they are $s$-wave superconductors, are believed to have superconducting gaps that change sign. We then consider the case of cuprate superconductors. We show that a nanowire on a steplike surface, especially in an orthorhombic material such as YBCO, can support Majorana zero modes at an elevated temperature.
16257249
The fast tracker architecture for the LHC baseline luminosity
A. Annovi,a M. Beretta,a, E. Bossini,b A. Boveia,c E. Brubaker,c F. Canelli,c V. Cavasinni,b F. Crescioli,b H. DeBerg,d M. Dell’Orso,b M. Dunford,c M. Franklin,e P. Giannetti,b A. Kapliy,c Y. K. Kim,c P. Laurelli,a A. McCarn,d C. Melachrinos,c C. Mills,e M. Neubauer,d J. Proudfoot, f , M. Piendibene,b G. Punzi,b F. Sarri,b L. Sartori,bh M. Shochet,c L. Tripiccione,i J. Tuggle,c I. Vivarelli,b G. Volpi∗,b K. Yorita,c J. Zhang. f aINFN Frascati, bUniv. and INFN of Pisa, cUniv. of Chicago, dUniv. of Illinois at Urbana-Champain, eHarvard Univ, f Argonne National Lab, hMarie Curie Fellowship, iUniv. and INFN Ferrara
122028207
Covariant harmonic oscillators and excited meson decays
We use the covariant harmonic-oscillator wave functions to formulate the vacuum quark-pair-creation model of three-meson vertices and meson-decay matrix elements. It is pointed out first that the harmonic-oscillator wave functions can be given a covariant probability interpretation. We then use this probability concept to construct the three-meson vertex function. Using a relativistic L-S coupling scheme, we calculate the decay amplitudes for the B $Yields$ $omega$$pi$ and A$sub 1$ $Yields$ rho$pi$ decays. For the B decay, the calculated polarization ratio turns out be in excellent agreement with the experimental value. For the A$sub 1$ decay, the calculated ratio is consistent with the present experimental value. We have also calculated the decay ratio for the well-established rho $Yields$ $pi$$pi$ and A$sub 2$ $Yields$ rho$pi$ decays. It is shown that the harmonic-oscillator wave functions produce a number which is very close to the experimental value. The limitations of the L-S coupling scheme are discussed.
118123985
Squeezed states, time-energy uncertainty relation, and Feynman's rest of the universe
Two illustrative examples are given for Feynman's rest of the universe. The first example is the two-mode squeezed state of light where no measurement is taken for one of the modes. The second example is the relativistic quark model where no measurement is possible for the time-like separation fo quarks confined in a hadron. It is possible to illustrate these examples using the covariant oscillator formalism. It is shown that the lack of symmetry between the position-momentum and time-energy uncertainty relations leads to an increase in entropy when the system is different Lorentz frames.