Scalar-fermion theories on the lattice

We study scalar-fermion models with Yukawa interaction on a space-time lat- tice. Such models can describe the Higgs sector of the Standard Model in the case when the Higgs particle is very heavy (few hundred GeV) and there are very heavy fermions whose masses are due to their Yukawa interactions w...

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Main Authors: Stephanov, M, Stephanov, Mikhail Alexeevich
Other Authors: Teper, M
Format: Thesis
Language:English
Published: 1994
Subjects:
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author Stephanov, M
Stephanov, Mikhail Alexeevich
author2 Teper, M
author_facet Teper, M
Stephanov, M
Stephanov, Mikhail Alexeevich
author_sort Stephanov, M
collection OXFORD
description We study scalar-fermion models with Yukawa interaction on a space-time lat- tice. Such models can describe the Higgs sector of the Standard Model in the case when the Higgs particle is very heavy (few hundred GeV) and there are very heavy fermions whose masses are due to their Yukawa interactions with the Higgs field. We study a realistic model with four component scalar field as well as simplified models with one and two component scalar fields. We use a mean field approximation to calculate equations for critical lines in the large d (dimension of space-time) limit. These lines are in very good agreement with available Monte Carlo data for the models at d = 4. We calculate fermion correlation functions in the mean field and large d approximations to study properties of different phases in the lattice models. We find two distinct phases with vanishing expectation values of the scalar field. One (at small Yukawa coupling Y) contains massless fermions, while in the other (at large F) the fermions have masses larger than the scale given by the inverse lattice spacing. We find that in the latter phase fermions can form bosonic bound states. These states show up as poles in a four-fermion correlator. We discuss pos- sible continuum limits in the lattice scalar-fermion models. In particular, we show that a theory defined near the critical line separating the disordered phase from the phase with antiferromagnetic order is not unitary.
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spelling oxford-uuid:555a30de-2df9-4d39-b2dc-1974398911f72024-12-08T13:35:32ZScalar-fermion theories on the latticeThesishttp://purl.org/coar/resource_type/c_db06uuid:555a30de-2df9-4d39-b2dc-1974398911f7FermionsScalar field theoryLattice field theoryEnglishPolonsky Theses Digitisation Project1994Stephanov, MStephanov, Mikhail AlexeevichTeper, MTeper, MWe study scalar-fermion models with Yukawa interaction on a space-time lat- tice. Such models can describe the Higgs sector of the Standard Model in the case when the Higgs particle is very heavy (few hundred GeV) and there are very heavy fermions whose masses are due to their Yukawa interactions with the Higgs field. We study a realistic model with four component scalar field as well as simplified models with one and two component scalar fields. We use a mean field approximation to calculate equations for critical lines in the large d (dimension of space-time) limit. These lines are in very good agreement with available Monte Carlo data for the models at d = 4. We calculate fermion correlation functions in the mean field and large d approximations to study properties of different phases in the lattice models. We find two distinct phases with vanishing expectation values of the scalar field. One (at small Yukawa coupling Y) contains massless fermions, while in the other (at large F) the fermions have masses larger than the scale given by the inverse lattice spacing. We find that in the latter phase fermions can form bosonic bound states. These states show up as poles in a four-fermion correlator. We discuss pos- sible continuum limits in the lattice scalar-fermion models. In particular, we show that a theory defined near the critical line separating the disordered phase from the phase with antiferromagnetic order is not unitary.
spellingShingle Fermions
Scalar field theory
Lattice field theory
Stephanov, M
Stephanov, Mikhail Alexeevich
Scalar-fermion theories on the lattice
title Scalar-fermion theories on the lattice
title_full Scalar-fermion theories on the lattice
title_fullStr Scalar-fermion theories on the lattice
title_full_unstemmed Scalar-fermion theories on the lattice
title_short Scalar-fermion theories on the lattice
title_sort scalar fermion theories on the lattice
topic Fermions
Scalar field theory
Lattice field theory
work_keys_str_mv AT stephanovm scalarfermiontheoriesonthelattice
AT stephanovmikhailalexeevich scalarfermiontheoriesonthelattice