عنوان

Nonperturbative studies of scalar and scalar-fermion quantum field theories at zero and finite temperature using the Gaussian effective potential

Number

TLpq303679514

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Nonperturbative studies of scalar and scalar-fermion quantum field theories at zero and finite temperature using the Gaussian effective potential

General Material Designation

[Thesis]

First Statement of Responsibility

G. A. Hajj

Subsequent Statement of Responsibility

P. M. Stevenson

Name of Publisher, Distributor, etc.

Rice University

Date of Publication, Distribution, etc.

1988

Specific Material Designation and Extent of Item

159

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Rice University

Text preceding or following the note

1988

Text of Note

The Gaussian effective potential (GEP), a non-perturbative approach to study quantum field theory, is applied to scalar and scalar-fermion models. We study the scalar usd\phi\sp6usd field coupled to fermions through g{\rm B}\phi\overline{\psi}\psi or g{\rm B}\phi\sp2\overline{\psi}\psi in 2 and 3 space-time dimensions. In addition, we derive the finite temperature (T > 0) GEP from first principles and apply it to study these models at T > 0. Also the Autonomous usd\lambda\phi\sp4usd, coupled to fermions through a Yukawa term (g{\rm B}\phi\overline{\psi}\psi), is examined in 4 dimensions at T > 0. In all these models, in order to obtain stable theories, it is found that gB must vanish as 1/log(Muv), 1/Muv or 1/Msp{\rm uv}{2} in 2, 3 or 4 dimensions respectively, Muv being an ultraviolet cutoff which is sent to infinity. The contribution of fermions to the GEP, however, is nonvanishing. It is also found that for the class of theories discussed, symmetry, if broken, is restored above a critical temperature. The coupling constant parameter space for each model is studied carefully, and regions where symmetry breaking occurs are determined both at zero and finite temperature.

Particle physics

Pure sciences

G. A. Hajj

P. M. Stevenson

Electronic name

p

[Thesis]

276903

a

Y