Geometric Approach to Quantum Statistical Mechanics and Application to Casimir Energy and Friction Properties

A geometric approach to general quantum statistical systems (including the harmonic oscillator) is presented. It is applied to Casimir energy and the dissipative system with friction. We regard the (N+1)-dimensional Euclidean {\it coordinate} system (X$^i$,$\tau$) as the quantum statistical system of N quantum (statistical) variables (X$^i$) and one {\it Euclidean time} variable ($\tau$). Introducing paths (lines or hypersurfaces) in this space (X$^i$,$\tau$), we adopt the path-integral method to quantize the mechanical system. This is a new view of (statistical) quantization of the {\it mechanical} system. The system Hamiltonian appears as the {\it area}. We show quantization is realized by the {\it minimal area principle} in the present geometric approach. When we take a {\it line} as the path, the path-integral expressions of the free energy are shown to be the ordinary ones (such as N harmonic oscillators) or their simple variation. When we take a {\it hyper-surface} as the path, the system Hamiltonian is given by the {\it area} of the {\it hyper-surface} which is defined as a {\it closed-string configuration} in the bulk space. In this case, the system becomes a O(N) non-linear model. We show the recently-proposed 5 dimensional Casimir energy (ArXiv:0801.3064,0812.1263) is valid. We apply this approach to the visco-elastic system, and present a new method using the path-integral for the calculation of the dissipative properties.Comment: 20 pages, 8 figures, Proceedings of ICFS2010 (2010.9.13-18, Ise-Shima, Mie, Japan

Some Properties of Domain Wall Solution in the Randall-Sundrum Model

Properties of the domain wall (kink) solution in the 5 dimensional Randall-Sundrum model are examined both {\it analytically} and {\it numerically}. The configuration is derived by the bulk Higgs mechanism. We focus on 1) the convergence property of the solution, 2) the stableness of the solution, 3) the non-singular property of the Riemann curvature, 4) the behaviours of the warp factor and the Higgs field. It is found that the bulk curvature changes the sign around the surface of the wall. We also present some {\it exact} solutions for two simple cases: a) the no potential case, b) the cosmological term dominated case. Both solutions have the (naked) curvature singularity. We can regard the domain wall solution as a singularity resolution of the exact solutions.Comment: Typographical error correction for publication. 16 pages, 4 figure

Solitons in Chern-Simons theories of nonrelativistic CP^{N-1} models: Spin textures in the quantum Hall effect

Topological solitons in CP^{N-1} models coupled with Chern-Simons gauge theory and a Hopf term are studied both analytically and numerically.These models are low-energy effective theories for the quantum Hall effect with internal degrees of freedom, like that in bilayer electron systems. We explicitly show that the CP^{N-1} models describe quite well spin textures in the original Chern-Simons theory of bosonized electrons.Comment: Latex, 19 pages, 6 figure

The Finiteness Requirement for Six-Dimensional Euclidean Einstein Gravity

The finiteness requirement for Euclidean Einstein gravity is shown to be so stringent that only the flat metric is allowed. We examine counterterms in 4D and 6D Ricci-flat manifolds from general invariance arguments.Comment: 15 pages, Introduction is improved, many figures(eps

Dixon-Souriau equations from a 5-dimensional spinning particle in a Kaluza-Klein framework

The dimensional reduction of Papapetrou equations is performed in a 5-dimensional Kaluza-Klein background and Dixon-Souriau results for the motion of a charged spinning body are obtained. The splitting provides an electric dipole moment, and, for elementary particles, the induced parity and time-reversal violations are explained.Comment: 20 pages, to appear on Physics Letters

Quarks, Gluons and Frustrated Antiferromagnets

The Contractor Renormalization Group method (CORE) is used to establish the equivalence of various Hamiltonian free fermion theories and a class of generalized frustrated antiferromagnets. In particular, after a detailed discussion of a simple example, it is argued that a generalized frustrated SU(3) antiferromagnet whose single-site states have the quantum numbers of mesons and baryons is equivalent to a theory of free massless quarks. Furthermore, it is argued that for slight modification of the couplings which define the frustrated antiferromagnet Hamiltonian, the theory becomes a theory of quarks interacting with color gauge-fields.Comment: 21 pages, Late

Microscopic analysis of the chemical reaction between Fe(Te,Se) thin films and underlying CaF2_2

To understand the chemical reaction at the interface of materials, we performed a transmission electron microscopy (TEM) observation in four types of Fe(Te,Se) superconducting thin films prepared on different types of substrates: CaF2 substrate, CaF2 substrate with a CaF2 buffer layer, CaF2 substrate with a FeSe buffer layer, and a LaAlO3 substrate with a CaF2 buffer layer. Based on the energy-dispersive X-ray spectrometer (EDX) analysis, we found possible interdiffusion between fluorine and selenium that has a strong influence on the superconductivity in Fe(Te,Se) films. The chemical interdiffusion also plays a significant role in the variation of the lattice parameters. The lattice parameters of the Fe(Te,Se) thin films are primarily determined by the chemical substitution of anions, and the lattice mismatch only plays a secondary role.Comment: 30 pages, 9 figur

Effective gauge field theory of the t-J model in the charge-spin separated state and its transport properties

We study the slave-boson t-J model of cuprates with high superconducting transition temperatures, and derive its low-energy effective field theory for the charge-spin separated state in a self-consistent manner. The phase degrees of freedom of the mean field for hoppings of holons and spinons can be regarded as a U(1) gauge field, $A_i$. The charge-spin separation occurs below certain temperature, $T_{\rm CSS}$, as a deconfinement phenomenon of the dynamics of $A_i$. Below certain temperature $T_{\rm SG} (< T_{\rm CSS})$, the spin-gap phase develops as the Higgs phase of the gauge-field dynamics, and $A_i$ acquires a mass $m_A$. The effective field theory near $T_{\rm SG}$ takes the form of Ginzburg-Landau theory of a complex scalar field $\lambda$ coupled with $A_i$, where $\lambda$ represents d-wave pairings of spinons. Three dimensionality of the system is crucial to realize a phase transition at $T_{\rm SG}$. By using this field theory, we calculate the dc resistivity $\rho$. At $T > T_{\rm SG}$, $\rho$ is proportional to $T$. At $T < T_{\rm SG}$, it deviates downward from the $T$-linear behavior as $\rho \propto T \{1 -c(T_{\rm SG}-T)^d \}$. When the system is near (but not) two dimensional, due to the compactness of the phase of the field $\lambda$, the exponent $d$ deviates from its mean-field value 1/2 and becomes a nonuniversal quantity which depends on temperature and doping. This significantly improves the comparison with the experimental data

The role of H2S bioavailability in endothelial dysfunction

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Endothelial dysfunction (EDF) reflects pathophysiological changes in the phenotype and functions of endothelial cells that result from and/or contribute to a plethora of cardiovascular diseases. We review the role of hydrogen sulfide (H2S) in the pathogenesis of EDF, one of the fastest advancing research topics. Conventionally treated as an environment pollutant, H2S is also produced in endothelial cells and participates in the fine regulation of endothelial integrity and functions. Disturbed H2S bioavailability has been suggested to be a novel indicator of EDF progress and prognosis. EDF manifests in different forms in multiple pathologies, but therapeutics aimed at remedying altered H2S bioavailability may benefit all.This work has been supported by a Discovery Grant from Natural Sciences and Engineering Research council of Canada to RW. CS has been supported by the American Diabetes Association, the National Institutes of Health of USA and the Shriners Hospitals for Children. FI has been supported by the National Institutes of Health of USA. MW has been supported by the Medical Research Council of UK. AA has been supported by programme grants from British Heart Foundation (RG/09/001/25940), Medical Research Council (G0700288), Royal Society and European Union. AP has been supported through an Aristeia grant (1436) that is co-financed by the European Union (ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning”. MW and AP are supported by the COST Action BM1005 (ENOG: European network on gasotransmitters)

Criticality in the 2+1-dimensional compact Higgs model and fractionalized insulators

We use a novel method of computing the third moment M_3 of the action of the 2+1-dimensional compact Higgs model in the adjoint representation with q=2 to extract correlation length and specific heat exponents nu and alpha, without invoking hyperscaling. Finite-size scaling analysis of M_3 yields the ratio (1+alpha)/nu and 1/nu separately. We find that alpha and nu vary along the critical line of the theory, which however exhibits a remarkable resilience of Z_2 criticality. We propose this novel universality class to be that of the quantum phase transition from a Mott-Hubbard insulator to a charge-fractionalized insulator in two spatial dimensions.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let