相关论文: Massive fermion production in nonsingular superstr…
We describe a new mechanism, whose ingredients are realised in string compactifications, for the formation of cosmic (super)string networks. Oscillating string loops grow when their tension $\mu$ decreases with time. If $2H + \dot{\mu}/\mu…
Certain one-loop processes in eleven-dimensional supergravity compactified on T**2 determine exact, non-perturbative, terms in the effective action of type II string theories compactified on a circle. One example is the modular invariant…
In this paper we study fermion perturbations in four dimensional black holes of string theory, obtained either from a non-extreme configuration of three intersecting five-branes with a boost along the common string or from a non-extreme…
For a calculation of divergent fermion string amplitudes a regularization procedure invariant under the supermodular group is constructed. By this procedure superstring amplitudes of an arbitrary genus are calculated using both partition…
We study an interacting one-dimensional gas of spin-1/2 fermions with two-body losses. The dynamical phase diagram that characterises the approach to the stationary state displays a wide quantum-Zeno region, identified by a peculiar…
We present lattice results for spin-1/2 fermions at unitarity, where the effective range of the interaction is zero and the scattering length is infinite. We measure the spatial coherence of difermion pairs for a system of 6, 10, 14, 18,…
We investigate fermion--anti-fermion production in 1+1 dimensional QED using real-time lattice techniques. In this non-perturbative approach the full quantum dynamics of fermions is included while the gauge field dynamics can be accurately…
Pair particle creation is a well-known effect on the domain of field theory in curved space-time. It is shown that the entanglement generations for spin-0 and spin-1/2 modes are different in Friedmann-Robertson-Walker (FRW) space-time. We…
We investigate the real-time dynamics of U(1) and SU(N) gauge theories coupled to fermions on a lattice. While real-time lattice gauge theory is not amenable to standard importance sampling techniques, for a large class of time-dependent…
Based on a recent proposal according to which elementary particle masses could be generated by a non-perturbative dynamical phenomenon, alternative to the Higgs mechanism, we carry out lattice simulations of a model where a non-abelian…
In this paper, we study Schwinger pair production of charged massless particles in constant electric fields of finite-extent. Exploiting a map from the Dirac and Klein-Gordon equation to the harmonic oscillator, we find exact pair…
We investigate massless fermion production by a two-dimensional dilatonic black hole. Our analysis is based on the Bogoliubov transformation relating the outgoing fermion field observed outside the black hole horizon to the incoming field…
Gravitational particle production in time variable metric of an expanding universe is efficient only when the Hubble parameter $H$ is not too small in comparison with the particle mass. In standard cosmology, the huge value of the Planck…
A systematic method is presented for constructing increasingly precise sequences to refocus off-resonant spin evolution with severely limited control amplitude. Sequences obtained should be readily applicable to the case of electron spin…
We reconsider the question of mass generation for fermions coupled to a set of gauge bosons when the latter get their masses through the Goldstone bosons originating in a simple (i.e. not extended) technicolor sector. The fermion global…
The appearance of scalar/moduli fields in the early universe, as motivated by string theory, naturally leads to non-thermal "moduli cosmology". Such cosmology provides a consistent framework where the generation of radiation, baryons, and…
The spin-3/2 elementary particle, known as Rarita-Schwinger (RS) fermion, is described by a vector-spinor field {\psi}_{{\mu}{\alpha}}, whose number of components is larger than its independent degrees of freedom (DOF). Thus the RS…
QED with N species of massive fermions on a circle of circumference L is analyzed by bosonization. The problem is reduced to the quantum mechanics of the 2N fermionic and one gauge field zero modes on the circle, with nontrivial…
We derive an energy density functional for non-relativistic spin one-half fermions in the limit of a divergent two-body scattering length. Using an epsilon expansion around d=4-epsilon spatial dimensions we compute the coefficient of the…
We consider the scattering of fermions off antifermions with spin 1/2 and 3/2. Starting from helicity partial-wave scattering amplitudes we derive transformations that eliminate all kinematical constraints. Such amplitudes are expected to…