Related papers: Precise Quark Mass Dependence of Instanton Determi…
The fermion determinant in an instanton background for a quark field of arbitrary mass is studied using the Schwinger proper-time representation with WKB scattering phase shifts for the relevant partial-wave differential operators.…
This talk reports work done in collaboration with Jin Hur, Choonkyu Lee and Hyunsoo Min concerning the computation of the precise mass dependence of the fermion determinant for quarks in the presence of an instanton background. The result…
The precise quark mass dependence of the one-loop effective action in an instanton background has recently been computed [arXiv:hep-th/0410190]. The result interpolates smoothly between the previously known extreme small and large mass…
We present results for the fermion determinant in an external Yukawa-coupled scalar field, a quantity relevant to instanton and sphaleron transition rates as well as bubble nucleation occuring in the electroweak phase transition when the…
Our recent method to calculate renormalized functional determinants, the partial wave cutoff method, is extended for the evaluation of 4-D fermion one-loop effective action with arbitrary mass in certain types of radially symmetric,…
Recently the partial wave cutoff method was developed as a new calculational scheme for a functional determinant of quantum field theory in radial backgrounds. For the contribution given by an infinite sum of large partial waves, we derive…
Recently a new caculational scheme for effective actions in radial background fields was developed. The effective action is expressed as an infinite sum of partial-wave contributions, using the rotational symmetry of the system. The sum…
The fermion determinant in four-dimensional quantum electrodynamics in the presence of O(2)XO(3) symmetric background gauge fields with a nonvanishing global chiral anomaly is considered. It is shown that the leading mass singularity of the…
The Euclidean fermionic determinant in four-dimensional quantum electrodynamics is considered as a function of the fermionic mass for a class of $O(2)\times O(3)$ symmetric background gauge fields. These fields result in a determinant free…
In this talk it is discussed the derivation of low-frequencies part of quark determinant and partition function. As a first application, quark condensate is calculated beyond chiral limit with the account of O(m), O(1/N_c), O(1/N_c m) and…
We determine the fermionic corrections to the nucleation rate of bubbles at the electroweak phase transition. The fermion determinant is evaluated exactly and by using the gradient expansion. The gradient expansion is found to be a reliable…
An exact representation of the Euclidean fermion determinant in two dimensions for centrally symmetric, finite-ranged Abelian background fields is derived. Input data are the wave function inside the field's range and the scattering phase…
The quark determinant in the presence of a background gluon field is calculated in a large quark mass approach within a derivative expansion by considering quark sources. The resulting low-energy QCD Effective Field Theory (EFT) is valid…
We propose an improvement of the Diakonov-Petrov Effective Action on the basis of the Lee-Bardeen results for the quark determinant in the instanton field. This Improved Effective Action provides proper account of the current quark masses,…
Assuming the gluon field is well approximated by instanton configurations we derive a light quarks determinant and calculate its contribution to the specific heavy quarks correlators -- namely, the heavy quark propagator and heavy…
We use a novel method to calculate analytically the QCD instanton prefactor due to a quark field carrying a small mass parameter $m$. In the SU(2) instanton background of size $\rho$, the spinor effective action $\Gamma^F$ (in the minimal…
The Interacting Instanton Liquid Model is used to explore the role of instanton induced dynamics in hadron structure. To support the validity of this model in the chiral regime, the quark mass dependencies of several properties are shown to…
The path-integral of the fermionic oscillator with a time-dependent frequency is analyzed. We give the exact relation between the boundary condition to define the domain in which the path-integral is performed and the transition amplitude…
We review some recent work on nonperturbative properties of fermions and connections with chiral gauge theories. In particular, we consider one of the ultimate goals of this program: the understanding of the actual fermion mass spectrum. It…
The measurement of the branching fraction of a heavy quarkonium decaying into light hadronic final state at $e^+e^-$ colliders is revisited. In $e^+e^-$ annihilation experiments, background contributions from the continuum amplitude and its…