The Geometry of Large Causal Diamonds and the No Hair Property of Asymptotically de-Sitter Spacetimes

In a previous paper we obtained formulae for the volume of a causal diamond or Alexandrov open set $I^+(p) \cap I^-(q)$ whose duration $\tau(p,q)$ is short compared with the curvature scale. In the present paper we obtain asymptotic formulae valid when the point $q$ recedes to the future boundary ${\cal I}^+$ of an asymptotically de-Sitter spacetime. The volume (at fixed $\tau$) remains finite in this limit and is given by the universal formula $V(\tau) = {4\over 3}\pi (2\ln \cosh{\tau\over 2}-\tanh^2{\tau\over 2})$ plus corrections (given by a series in $e^{-t_q}$) which begin at order $e^{-4t_q}$. The coefficents of the corrections depend on the geometry of ${\cal I}^+$. This behaviour is shown to be consistent with the no-hair property of cosmological event horizons and with calculations of de-Sitter quasinormal modes in the literature.Comment: 13 pages, 2 figures, Latex; references adde

Hepatosplenic Gamma/Delta T-Cell Lymphoma Masquerading as Alcoholic Hepatitis and Methadone Withdrawal

Hepatosplenic gamma/delta T-cell lymphoma is a rare neoplasm of mature gamma/delta T-cells with sinusoidal infiltration of spleen, liver, and bone marrow. Patients are predominantly adolescent and young adult males and usually present with marked hepatosplenomegaly. Pancytopenia is another common finding. Despite an initial response to treatment, patients have a median survival of one to two years. In this report, we document a case of alcoholic hepatitis and methadone withdrawal masquerading unsuspected, hepatosplenic gamma/delta T-cell lymphoma with unusual CD20 positivity

The gut wall's potential as a partner for precision oncology in immune checkpoint treatment

The gut wall is the largest immune organ and forms a barrier through which gut microbiota interact with the immune system in the rest of the body. Gut microbiota composition plays a role in the strength and timing of the anticancer immune response on immune checkpoint inhibitors (ICI). Surprisingly, the effects of gut wall characteristics, such as physical barrier integrity, permeability, and activity and composition of the intestinal immune system, on response to ICI has received little attention. Here, we provide an overview of markers to characterize the gut wall and interventions that can modulate these gut wall characteristics. Finally, we present a future perspective on how these gut wall markers and interventions might be utilized and studied to improve ICI treatment strategies

On Gauge Invariance of Breit-Wigner Propagators

We present an approach to bosonic ($Z^0, W^{\pm}$) as well as fermionic (top-quark) Breit-Wigner propagators which is consistent with gauge invariance arguments. In particular, for the $Z^0$-boson propagator we extend previous analyses and show that the part proportional to $k_{\mu} k_{\nu}/M^2$ must be modified near the resonance. We derive a mass shift which agrees with results obtained elsewhere by different methods. The modified form of a resonant heavy fermion propagator is also given.Comment: 16 p., TeX, (final version

Epidemic processes with immunization

We study a model of directed percolation (DP) with immunization, i.e. with different probabilities for the first infection and subsequent infections. The immunization effect leads to an additional non-Markovian term in the corresponding field theoretical action. We consider immunization as a small perturbation around the DP fixed point in d<6, where the non-Markovian term is relevant. The immunization causes the system to be driven away from the neighbourhood of the DP critical point. In order to investigate the dynamical critical behaviour of the model, we consider the limits of low and high first infection rate, while the second infection rate remains constant at the DP critical value. Scaling arguments are applied to obtain an expression for the survival probability in both limits. The corresponding exponents are written in terms of the critical exponents for ordinary DP and DP with a wall. We find that the survival probability does not obey a power law behaviour, decaying instead as a stretched exponential in the low first infection probability limit and to a constant in the high first infection probability limit. The theoretical predictions are confirmed by optimized numerical simulations in 1+1 dimensions.Comment: 12 pages, 11 figures. v.2: minor correction

Quasiparticle Interactions in Fractional Quantum Hall Systems: Justification of Different Hierarchy Schemes

The pseudopotentials describing the interactions of quasiparticles in fractional quantum Hall (FQH) states are studied. Rules for the identification of incompressible quantum fluid ground states are found, based upon the form of the pseudopotentials. States belonging to the Jain sequence nu=n/(1+2pn), where n and p are integers, appear to be the only incompressible states in the thermodynamic limit, although other FQH hierarchy states occur for finite size systems. This explains the success of the composite Fermion picture.Comment: RevTeX, 10 pages, 7 EPS figures, submitted fo Phys.Rev.

Density functional method for nonequilibrium electron transport

We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density functional theory (DFT) as implemented in the well tested Siesta approach (which uses non-local norm-conserving pseudopotentials to describe the effect of the core electrons, and linear combination of finite-range numerical atomic orbitals to describe the valence states). We fully deal with the atomistic structure of the whole system, treating both the contact and the electrodes on the same footing. The effect of the finite bias (including selfconsistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. We relate the nonequilibrium Green's function expressions to the more transparent scheme involving the scattering states. As an illustration, the method is applied to three systems where we are able to compare our results to earlier ab initio DFT calculations or experiments, and we point out differences between this method and existing schemes. The systems considered are: (1) single atom carbon wires connected to aluminum electrodes with extended or finite cross section, (2) single atom gold wires, and finally (3) large carbon nanotube systems with point defects.Comment: 18 pages, 23 figure

Landau-Zener-Stuckelberg interferometry

A transition between energy levels at an avoided crossing is known as a Landau-Zener transition. When a two-level system (TLS) is subject to periodic driving with sufficiently large amplitude, a sequence of transitions occurs. The phase accumulated between transitions (commonly known as the Stuckelberg phase) may result in constructive or destructive interference. Accordingly, the physical observables of the system exhibit periodic dependence on the various system parameters. This phenomenon is often referred to as Landau-Zener-Stuckelberg (LZS) interferometry. Phenomena related to LZS interferometry occur in a variety of physical systems. In particular, recent experiments on LZS interferometry in superconducting TLSs (qubits) have demonstrated the potential for using this kind of interferometry as an effective tool for obtaining the parameters characterizing the TLS as well as its interaction with the control fields and with the environment. Furthermore, strong driving could allow for fast and reliable control of the quantum system. Here we review recent experimental results on LZS interferometry, and we present related theory.Comment: 34 single-column pages, 11 figure

Electronic transport in extended systems: Application to carbon nanotubes

Article on electronic transport in extended systems and the application to carbon nanotubes

Search for Single Top Production at LEP

Single top production in e+e- annihilations is searched for in data collected by the L3 detector at centre-of-mass energies from 189 to 209 GeV, corresponding to a total integrated luminosity of 634 pb-1. Investigating hadronic and semileptonic top decays, no evidence of single top production at LEP is obtained and upper limits on the single top cross section as a function of the centre-of-mass energy are derived. Limits on possible anomalous couplings, as well as on the scale of contact interactions responsible for single top production are determined