42,468 research outputs found
Quantum-classical interactions through the path integral
I consider the case of two interacting scalar fields, \phi and \psi, and use
the path integral formalism in order to treat the first classically and the
second quantum-mechanically. I derive the Feynman rules and the resulting
equation of motion for the classical field, which should be an improvement of
the usual semi-classical procedure. As an application I use this method in
order to enforce Gauss's law as a classical equation in a non-abelian gauge
theory. I argue that the theory is renormalizable and equivalent to the usual
Yang-Mills as far as the gauge field terms are concerned. There are additional
terms in the effective action that depend on the Lagrange multiplier field
\lambda that is used to enforce the constraint. These terms and their relation
to the confining properties of the theory are discussed.Comment: 16 pages, LaTeX, 1 fig, final version to appear in PR
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Time-series characteristics of UK commercial property returns: testing for multiple changes in persistence
The random-walk hypothesis, vis-Ă -vis asset prices , suggests that prices traded in a market cannot be predicted based on historical information. Employing unsecuritised UK commercial property returns, we analyze this hypothesis, investigating multiple changes in persistence in the series . Our results uncover multiple changes in persistence in both the aggregate and sector-specific data. We highlight some implications for academics, practitioners and regulators
Quantum Fermion Hair
It is shown that the Dirac operator in the background of a magnetic
%Reissner-Nordstr\"om black hole and a Euclidean vortex possesses normalizable
zero modes in theories containing superconducting cosmic strings. One
consequence of these zero modes is the presence of a fermion condensate around
magnetically charged black holes which violates global quantum numbers.Comment: 16pp (harvmac (l)) and 2 figs.(not included
Q-ball formation at the deconfinement temperature in large- QCD
The deconfinement phase transition in large- QCD is studied within the
framework of an effective Polyakov-loop model, where the potential has a U(1)
symmetry originating in the large- limit of a Z-symmetric model.
At the critical temperature, the shape of the effective potential allows the
existence of Q-balls as position-dependent fluctuations of the Polyakov loop.
Q-balls with spherical or axial symmetry are numerically obtained from the
equations of motion of the effective model under consideration. The physical
properties of these non-topological solitons (mass, charge and size) are
discussed, as well as their interpretation in terms of spinning "bubbles", with
various shapes, of deconfined matter surrounded by a confined environment.Comment: 21 pages, 8 figures ; v2 matches the published versio
Higgs Localization in Split Fermion Models
The flavor puzzle of the Standard Model is explained in split fermion models
by having the fermions localized and separated in an extra dimension. Many of
these models assume a certain profile for the Higgs VEV, usually uniform, or
confined to a brane, without providing a dynamical realization for it. By
studying the effect of the coupling between the Higgs and the localizer fields,
we obtain these scenarios as results, rather than ansaetze. Moreover, we
discuss other profiles and show that they are phenomenologically viable.Comment: 23 pages, 16 figures, based on an MSc thesi
Persistence of inflationary shocks: Implications for West African Monetary Union Membership
Plans are far advanced to form a second monetary union, the West African Monetary Zone
(WAMZ), in Africa. While much attention is being placed on convergence criteria and
preparedness of the five aspiring member states, less attention is being placed on the extent
to which the dynamics of inflation in individual countries are (dis)similar. This paper aims to
stimulate debate on the long term sustainability of the union by examining the dynamics of
inflation within these countries. Using Fractional Integration (FI) methods, we establish that
some significant differences exist among the countries. Shocks to inflation in Sierra Leone
are non mean reverting; results for The Gambia, Ghana and Guinea-Bissau suggest some
inflation persistence, despite being mean reverting. Some policy implications are discussed
and some warnings are raised
Effects of an extra U(1) axial condensate on the strong decays of pseudoscalar mesons
We consider a scenario (supported by some lattice results) in which a
U(1)-breaking condensate survives across the chiral transition in QCD. This
scenario has important consequences for the pseudoscalar-meson sector, which
can be studied using an effective Lagrangian model. In particular, generalizing
the results obtained in two previous papers, where the effects on the radiative
decays eta,eta' --> gamma gamma were studied, in this paper we study the
effects of the U(1) chiral condensate on the strong decays of the "light"
pseudoscalar mesons, i.e., eta,eta' --> 3pi^0; eta,eta' --> pi^+ pi^- pi^0;
eta' --> eta pi^0 pi^0; eta' --> eta pi^+ pi^-; and also on the strong decays
of an exotic ("heavy") SU(3)-singlet pseudoscalar state eta_X, predicted by the
model.Comment: One misprint in Eq. (2.10) has been eliminated; Eqs. (B.8) and (B.9)
in Appendix B have been corrected; 46 pages, 1 tabl
No supercritical supercurvature mode conjecture in one-bubble open inflation
In the path integral approach to false vacuum decay with the effect of
gravity, there is an unsolved problem, called the negative mode problem. We
show that the appearance of a supercritical supercurvature mode in the
one-bubble open inflation scenario is equivalent to the existence of a negative
mode around the Euclidean bounce solution. Supercritical supercurvature modes
are those whose mode functions diverge exponentially for large spatial radius
on the time constant hypersurface of the open universe. Then we propose a
conjecture that there should be ``no supercritical supercurvature mode''. For a
class of models that contains a wide variety of tunneling potentials, this
conjecture is shown to be correct.Comment: 11 pages, 3 postscript figures, tarred, gzipped. submitted to Phys.
Rev. D1
Exploring the Dynamics of Building Supply: A Duration Model of the Development Cycle
A noticeable omission in the existing body of applied real estate research is the lack of empirical analysis of the commercial development process. We address this shortcoming by utilizing a large panel database of individual building projects that in principle allows us to follow individual projects through various stages of their development life cycle. We begin by examining the basic distributional and time series characteristics of the development cycle, and then examine how these results vary by stage of construction, property sector and geography. We then estimate unconditional transition probabilities and finally, present preliminary results from a formal, nonparametric duration model.
Transport anomalies in a simplified model for a heavy electron quantum critical point
We discuss the transport anomalies associated with the development of heavy
electrons out of a neutral spin fluid using the large-N treatment of the
Kondo-Heisenberg lattice model. At the phase transition in this model the spin
excitations suddenly acquire charge. The Higgs process by which this takes
place causes the constraint gauge field to loosely ``lock'' together with the
external, electromagnetic gauge field. From this perspective, the heavy fermion
phase is a Meissner phase in which the field representing the difference
between the electromagnetic and constraint gauge field, is excluded from the
material. We show that at the transition into the heavy fermion phase, both the
linear and the Hall conductivity jump together. However, the Drude weight of
the heavy electron fluid does not jump at the quantum critical point, but
instead grows linearly with the distance from the quantum critical point,
forming a kind of ``gossamer'' Fermi-liquid.Comment: 15 pages, 3 figures. Small change in references in v
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