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

Time-series characteristics of UK commercial property returns: testing for multiple changes in persistence

The random-walk hypothesis, vis-à-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

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

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

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

Ultraviolet Properties of the Higgs Sector in the Lee-Wick Standard Model

The Lee-Wick (LW) Standard Model (SM) offers a new solution to the hierarchy problem. We discuss, using effective potential techniques, its peculiar ultraviolet (UV) behaviour. We show how quadratic divergences in the Higgs mass Mh cancel as a result of the unusual dependence of LW fields on the Higgs background (in a manner reminiscent of Little Higgses). We then extract from the effective potential the renormalization group evolution of the Higgs quartic coupling lambda above the LW scale. After clarifying an apparent discrepancy with previous results for the LW Abelian Higgs model we focus on the LWSM. In contrast with the SM case, for any Mh, lambda grows monotonically and hits a Landau pole at a fixed trans-Planckian scale (never turning negative in the UV). Then, the perturbativity and stability bounds on Mh disappear. We identify a cutoff ~10^{16} GeV for the LWSM due to the hypercharge gauge coupling hitting a Landau pole. Finally, we also discuss briefly the possible impact of the UV properties of the LW models on their behaviour at finite temperature, in particular regarding symmetry nonrestoration.Comment: 25 pages, 3 figure

A Second Shell in the Fornax dSph Galaxy

In the search for tidal structure in Galactic satellite systems, we have conducted a photometric survey over a 10 square degree area centred on the Fornax dSph galaxy. The survey was made in two colours, and the resulting colour-magnitude data were used as a mask to select candidate Fornax RGB stars, thereby increasing the contrast of Fornax stars to background sources in the outer regions. Previously, we reported the presence of a shell (age 2 Gyr) located towards the centre of Fornax. In this contribution we reveal a second shell, significantly larger than the first, located 1.3 degrees NW from the centre of Fornax, outside the nominal tidal radius. Moreover, the distribution of Fornax RGB stars reveals two lobes extending to the spatial limit of our survey, and aligned with the minor axis and with the two shells. These results support the hypothesis of a merger between Fornax and a gas-rich companion approximately 2 Gyr ago.Comment: Four pages,accepted for the Publications of the Astronomical Society of Australia. Contribution the annual ASA meeting, Brisbane 200

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.

Q-ball formation at the deconfinement temperature in large-NcN_c QCD

The deconfinement phase transition in large-$N_c$ QCD is studied within the framework of an effective Polyakov-loop model, where the potential has a U(1) symmetry originating in the large-$N_c$ limit of a Z$_{N_c}$-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