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Bum-Hoon Lee

Publications and source records attributed to Bum-Hoon Lee.

170 records · Page 10Linked to original sources
arXiv1998

Thermodynamic Properties of Generalized Exclusion Statistics

We analytically calculate some thermodynamic quantities of an ideal $g$-on gas obeying generalized exclusion statistics. We show that the specific heat of a $g$-on gas ($g \neq 0$) vanishes linearly in any dimension as $T \to 0$ when the particle number is conserved and exhibits an interesting dual symmetry that relates the particle-statistics at $g$ to the hole-statistics at $1/g$ at low temperatures. We derive the complete solution for the cluster coefficients $b_l(g)$ as a function of Haldane's statistical interaction $g$ in $D$ dimensions. We also find that the cluster coefficients $b_l(g)$ and the virial coefficients $a_l(g)$ are exactly mirror symmetric ($l$=odd) or antisymmetric ($l$=even) about $g=1/2$. In two dimensions, we completely determine the closed forms about the cluster and the virial coefficients of the generalized exclusion statistics, which exactly agree with the virial coefficients of an anyon gas of linear energies. We show that the $g$-on gas with zero chemical potential shows thermodynamic properties similar to the photon statistics. We discuss some physical implications of our results.

cond-mat↗
arXiv1998

Non-Abelian Ramond-Neveu-Schwarz String Theory

We construct a locally supersymmetric worldsheet formulation of a non-Abelian Ramond-Neveu-Schwarz (NARNS) string theory where the string coordinates are noncommuting matrices in a group U(N). This is described by the two dimensional supergravity coupled to supersymmetric Yang-Mills fields and adjoint matters in the gauge group U(N). We show that our NARNS string theory has a free string limit where it becomes N-copies of usual RNS string which can be described by the orbifold conformal field theory corresponding to the covariant worldsheet version of the Matrix string theory of Dijkgraaf, Verlinde and Verlinde. In the weak coupling limit, i.e. $g_s \to 0$ where $g_s$ is the coupling constant of our theory related with the Yang-Mills coupling as $g_{YM}^{-2}=α' g_s^2$, a new additional dimension appears in the string spectrum and it can be speculatively interpreted as the compactified eleven dimensional coordinate whose dynamics is given by an orbifold O(N) sigma model.

hep-th↗
arXiv1998

Perturbative QCD Analysis of B to pi and B to rho Transitions

We calculate the form factors of $B\toπ$ and $B\toρ$ heavy to light transition matrix elements by using the factorization formalism of perturbative QCD. We obtain them at $q^2=0$ and show their dependences on the parameter $ε$ of the B meson distribution amplitude. We also obtain the form factors as functions of $q^2$ in the region $0\le q^2 \le M_B^2/2$. The relations among the form factors are found in the limit of $m_π/M_B=0$, $m_ρ/M_B=0$, ${M_b/M_B}=1$ and $(1-x)<<1$.

hep-ph↗
arXiv1995

BRST Cohomology and Its Application to QED

We construct the BRST cohomology under a positive definite inner product and obtain the Hodge decomposition theorem at a non-degenerate state vector space $V$. The harmonic states isomorphic with a BRST cohomology class correspond to the physical Hilbert space with positive norm as long as the completeness of $Q_{BRST}$ is satisfied. We explicitly define ``co-BRST'' operator and analyze the quartet mechanism in QED.

hep-th↗
arXiv1995

Lie algebra cohomology and group structure of gauge theories

We explicitly construct the adjoint operator of coboundary operator and obtain the Hodge decomposition theorem and the Poincaré duality for the Lie algebra cohomology of the infinite-dimensional gauge transformation group. We show that the adjoint of the coboundary operator can be identified with the BRST adjoint generator $Q^{\dagger}$ for the Lie algebra cohomology induced by BRST generator $Q$. We also point out an interesting duality relation - Poincaré duality - with respect to gauge anomalies and Wess-Zumino-Witten topological terms. We consider the consistent embedding of the BRST adjoint generator $Q^{\dagger}$ into the relativistic phase space and identify the noncovariant symmetry recently discovered in QED with the BRST adjoint Nöther charge $Q^{\dagger}$.

hep-th↗
arXiv1994

Quantum Aspects of Supersymmetric Maxwell Chern-Simons Solitons

We study the various quantum aspects of the $N=2$ supersymmetric Maxwell Chern-Simons vortex systems. The fermion zero modes around the vortices will give rise the degenerate states of vortices. We analyze the angular momentum of these zero modes and apply the result to get the supermultiplet structures of the vortex. The leading quantum correction to the mass of the vortex coming from the mode fluctuations is also calculated using various methods depending on the value of the coefficient of the Chern-Simons term $κ$ to be zero, infinite and finite, separately. The mass correction is shown to vanish for all cases. Fermion numbers of vortices are also discussed.

hep-th↗
arXiv1993

Schrödinger Fields on the Plane with $[U(1)]^N$ Chern-Simons Interactions and Generalized Self-dual Solitons

A general non-relativistic field theory on the plane with couplings to an arbitrary number of abelian Chern-Simons gauge fields is considered. Elementary excitations of the system are shown to exhibit fractional and mutual statistics. We identify the self-dual systems for which certain classical and quantal aspects of the theory can be studied in a much simplified mathematical setting. Then, specializing to the general self-dual system with two Chern-Simons gauge fields (and non-vanishing mutual statistics parameter), we present a systematic analysis for the static vortexlike classical solutions, with or without uniform background magnetic field. Relativistic generalizations are also discussed briefly.

hep-th↗