Sep 10, 2013 - Abstract. - We study magnetic-monopole excitations in the framework of the lattice Georgi-. Glashow model. With the appropriate definition of ...
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Magnetic-Monopole Excitations in the Georgi-Glashow Model
This content has been downloaded from IOPscience. Please scroll down to see the full text. 1989 Europhys. Lett. 9 23 (http://iopscience.iop.org/0295-5075/9/1/005) View the table of contents for this issue, or go to the journal homepage for more
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1 May 1989
EUROPHYSICS LETTERS
Europhys. Lett., 9 (l),pp. 23-28 (1989)
Magnetic-Monopole Excitations in Model.
the
Georgi-Glashow
V. AZCOITI(*),A. CRUZ(*),G. DI CARLO(**)(***) A. F. GRILLO(**)and A. TARANCON(*)($) (*) Departamento de Fisica Teorica, Faculdad de Ciencias, 50009 - Zaragoza, Spain (**) INFN, Laboratom' Nazionali d i Frascati, P.0.B 13 - Frascati, Italy (***) Istituto d i Fisica, Universita dell'Aquila, Italy (received 14 November 1988; accepted in final form 27 February 1989) PACS. PACS. PACS. PACS.
14.80H - Magnetic monopoles. 11.10N - Gauge field theories. 12.30 - Models of weak interactions. 64.60 - General studies of phase transitions.
Abstract. - We study magnetic-monopole excitations in the framework of the lattice GeorgiGlashow model. With the appropriate definition of the lattice e.m. stress tensor we find that the vacuum in the confining phase is characterized by a large density of magnetic monopoles, and the Higgs phase by the presence of monopoles as particles in the spectrum. An order parameter, related to the photon mass through Gauss law, is introduced.
In recent times the SU(B)-Higgs model has been the subject of increasing interest in particular regarding the nonperturbative lattice analysis of the phenomenon of spontaneous symmetry breaking and mass generation in the gauge sector. Rather surprising results on this subject have already been found, having shown dynamical charge confinement both in the >configuration of the Higgs field is allowed, though not dictated, by the boundary conditions. In fig. 3a), b) we present the total magnetic charge as a function of the Monte Carlo .time)> for p = 0.5 and y = 5 and 2.5, respectively. We see that, while in the confining phase this quantity is essentially randomly distributed, in the Higgs one there is clear indication of (meta)stability of the magnetic charge, with stability increasing with lattice
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EUROPHYSICS LETTERS
size, as we have checked in a 44 lattice. Of course magnetic monopoles in the lattice are not guaranteed to be absolutely stable. We think to have presented a convincing evidence that classical finite-energy solutions, i.e. magnetic monopoles of the t’Hooft-Polyakov type are important in the quantized GeorgiGlashow model on the lattice. One can think of the vacuum in the confining phase as a condensate of (anti)monopoles. On the other hand, in the Higgs phase there is evidence that monopoles are present as particles in the spectrum of the theory. The more interesting problem left open is the fact that it has been shown that dynamical matter charges are confined also in the Higgs phase [2]: we do not know the relation of this with the fact that monopoles seem to exist as free particles, as well as the fact that the photon stays massless.
Additional remark. While this paper was written, we have received a paper (M. L. Laursen and M. Muller-Preussker, NBI-HE-87-65) on a similar subject.
*** This work has been carried out in the context of an INFN-CAICYT collaboration. We thank both institutions for their financial support.
REFERENCES [I] EVERTZ H. G. et al., Phys. Lett. B , 175 (1986) 335. A., INFN-LNF 87/86, to appear [2] AZCOITIV., CRUZA., DI CARLOG., GRILLOF. G. and TARANCON in Phys. Lett. B. [3] LEE I.-H. and SHIGEMITSU J., Nucl. Phys. B , 263 (1986) 280. [4] MITRIJUSHIN V. K., MULLER-PREUSSKER M. and ZADOROZHNY A. M., Phys. Lett. B , 199 (1987) G., SEIXAS J. and TEPERM., Phys. Lett. B , 151 (1985) who use a definition 82; see also: SCHIEROLZ which agrees with eq. (3) at large distances; KRONFELDA. S., SCHIEROLZ G. and WIESE U . J . , Nucl. Phys. B , 293 (1987) 461. D., Phys. Rev. D , 22 (1980) 2478; HONDAM., Phys. Lett. B , 109 [5] DE GRANDT. A. and TOUSSAINT (1982) 467. [6] LANGC. B., REBBI C. and VIRASOROM., Phys. Lett. B , 104 (1981) 294; BAIERR., GAVAIR. V. and LANG C. B.. BI-TP 86/09.
