3,381 research outputs found
Magnetic Oscillations in the Nambu - Jona-Lasinio model
The phase structure of a simple Nambu-Jona-Lasinio model has been
investigated at non-zero values of and H, where H is an external magnetic
field and is the chemical potential. On this basis magnetic oscillations
effects were considered. It was shown that there are standard (periodic) van
Alphen-de Haas magnetic oscillations of some thermodynamical quantities,
including magnetization, pressure and particle density in the NJL system.
Besides, we have found non-standard, i.e. non-periodic, magnetic oscillations,
since the frequency of oscillations is a H-dependent quantity. Finally, there
arises an oscillating behaviour not only for thermodynamical quantities, but
also for a dynamical quantity like the quark mass. The possibility for magnetic
oscillations of some physical quantities inside neutron stars is discussed.Comment: RevTeX, 12 pages; Talk given by K.G. Klimenko at the International
Workshop on Hadron Physics, 10-15 September 1999, Coimbra, Portuga
Diquarks in the color--flavor locked phase of dense quark matter
Diquark excitations of dense quark matter are considered in the framework of
the Nambu -- Jona-Lasinio model with three types of massless quarks in the
presense of a quark number chemical potential . We investigate the
effective action of meson- and diquark fields at sufficiently high values of
, where the color--flavor locked (CFL) phase is realized, and prove the
existence of NG-bosons in the sector of pseudoscalar diquarks. In the sector of
scalar diquarks an additional NG-boson is found, corresponding to the
spontaneous breaking of the U(1) baryon symmetry in the CFL phase. Finally,
the existence of massive scalar and pseudoscalar diquark excitations is
demonstrated.Comment: 10 pages, 2 figures; version accepted for publication in PR
Competition of Color Ferromagnetic and Superconductive States in a Quark-Gluon System
The possibility of color ferromagnetism in an SU(2) gauge field model is
investigated. The conditions allowing a stable color ferromagnetic state of the
quark system in the chromomagnetic field occupying small domains are
considered. A phase transition between this state and the color superconducting
state is considered. The effect of finite temperature is analyzed.Comment: 21 pages, 4 Postscript figure
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