Canonical Quantization for a Relativistic Neutral Scalar Field in Non-equilibrium Thermo Field Dynamics

A relativistic neutral scalar field is investigated in non-equilibrium thermo field dynamics. The canonical quantization is applied to the fields out of equilibrium. Because the thermal Bogoliubov transformation becomes time-dependent, the equations of motion for the ordinary unperturbed creation and annihilation operators are modified. This forces us to introduce a thermal counter term in the interaction Hamiltonian which generates additional radiative corrections. Imposing the self-consistency renormalization condition on the total radiative corrections, we obtain the quantum Boltzmann equation for the relativistic scalar field.Comment: 20 pages, 2 figure

Dependence of a self-assembled amphiphile structure on the interaction between hydrophilic groups

In a previous study (2005 Comput. Phys. Commun. 169, 139?143), we clarified the dependence of the phase structure on the hydrophilicity of an amphiphilic molecule by varying the interaction potential between the hydrophilic molecule and water (a_AW) in a dissipative particle dynamics (DPD) simulation using the Jury model. In the present paper, we perform another DPD simulation using the previous model to investigate the dependence of the interaction potential between adjacent hydrophilic groups on the phase structure. By varying the coefficient of the interaction potential between adjacent hydrophilic groups a_AA (a_AA = 15, 25, 40 and 250) at a dimensionless temperature of T = 0.5 and a concentration of amphiphilic molecules in water of φ = 50%, hexagonal (a_AA = 14, 25, 40) and micellar (a_AA = 250) phases were observed. In comparison with the previous results, the dependence of the A?B dimer’s shape on a_AA was determined to be weaker than that on a_AW. Therefore, it is concluded that the solvent waterWplays an important role in aggregation of the A?B dimers

Phase Diagram for Self-assembly of Amphiphilic Molecule C12E6 by Dissipative Particle Dynamics Simulation

In a previous study, dissipative particle dynamics simulation was used to qualitatively clarify the phase diagram of the amphiphilic molecule hexaethylene glycol dodecyl ether (C12E6). In the present study, the hydrophilicity dependence of the phase structure was clarified qualitatively by varying the interaction potential between hydrophilic molecules and water molecules in a dissipative particle dynamics (DPD) simulation using the Jury model. By varying the coefficient of the interaction potential $x$ between hydrophilic beads and water molecules as x=-20, 0, 10, and 20, at a dimensionless temperature of T=0.5 and a concentration of amphiphilic molecules in water of phi=50% the phase structures grew to lamellar (x=-20), hexagonal (x=0), and micellar (x=10) phases. For x=20, phase separation occurs between hydrophilic beads and water molecules

A non-Hermitian analysis of strongly correlated quantum systems

We study a non-Hermitian generalization of strongly correlated quantum systems in which the transfer energy of electrons is asymmetric. It is known that a non-Hermitian critical point is equal to the inverse localization length of a Hermitian non-interacting random electron system. We here conjecture that we can obtain in the same way the correlation length of a Hermitian interacting non-random system. We confirm the conjecture using exact solutions and numerical finite-size data of the Hubbard model and the antiferromagnetic XXZ model in one dimension

An Efficient, One-Pot Synthesis of Fosfomycin Dialkyl Esters from (R)-2-Tosyloxypropanal

(R)-2-Tosyloxypropanal (4) was prepared from D-mannitol in a 7-step sequence (51% overall yield). Addition of dialkyl phosphonates to 4 in the presence of titanium isopropoxide and the subsequent treatment with DBU stereoselectively afforded, in one-pot, fosfomycin dimethyl (5a) and dibenzyl (5b) esters both in 58% isolated yield

Superconductivity protected by spin-valley locking in ion-gated MoS2

Symmetry-breaking has been known to play a key role in noncentrosymmetric superconductors with strong spin-orbit-interaction (SOI). The studies, however, have been so far mainly focused on a particular type of SOI, known as Rashba SOI, whereby the electron spin is locked to its momentum at a right-angle, thereby leading to an in-planar helical spin texture. Here we discuss electric-field-induced superconductivity in molybdenum disulphide (MoS2), which exhibits a fundamentally different type of intrinsic SOI manifested by an out-of-plane Zeeman-type spin polarization of energy valleys. We find an upper critical field of approximately 52 T at 1.5 K, which indicates an enhancement of the Pauli limit by a factor of four as compared to that in centrosymmetric conventional superconductors. Using realistic tight-binding calculations, we reveal that this unusual behaviour is due to an inter-valley pairing that is symmetrically protected by Zeeman-type spin-valley locking against external magnetic fields. Our study sheds a new light on the interplay of inversion asymmetry with SOI in confined geometries, and its unprecedented role in superconductivity.Comment: 37 pages, 11 figures, http://meetings.aps.org/Meeting/MAR15/Session/G11.1

Neutron-scattering study of yttrium iron garnet

The nuclear and magnetic structure and full magnon dispersions of yttrium iron garnet Y$_3$Fe$_5$O$_{12}$ have been studied by neutron scattering. The refined nuclear structure is distorted to a trigonal space group of $R\bar{3}$. The highest-energy dispersion extends up to 86 meV. The observed dispersions are reproduced by a simple model with three nearest-neighbor-exchange integrals between 16$a$ (octahedral) and 24$d$ (tetrahedral) sites, $J_{aa}$, $J_{ad}$, and $J_{dd}$, which are estimated to be 0.00$\pm$0.05, $-$2.90$\pm$0.07, and $-$0.35$\pm$0.08 meV, respectively. The lowest-energy dispersion below 14 meV exhibits a quadratic dispersion as expected from ferromagnetic magnons. The imaginary part of $q$-integrated dynamical spin susceptibility $\chi$"($E$) exhibits a square-root energy-dependence in the low energies. The magnon density of state is estimated from the $\chi$"($E$) obtained on an absolute scale. The value is consistent with a single polarization mode for the magnon branch expected theoretically.Comment: 9 pages, 9 figure