arXiv subjects

Toru Suzuki

Publications and source records attributed to Toru Suzuki.

12 recordsLinked to original sources

arXiv2019

LabPipe: an extensible informatics platform to streamline management of metabolomics data and metadata

Summary: Data management in clinical metabolomics studies is often inadequate. To improve this situation we created LabPipe to provide a guided, customisable approach to study-specific sample collection. It is driven through a local client which manages the process and pushes local data to a remote server through an access controlled web API. The platform is able to support data management for different sampling approaches across multiple sites / studies and is now an essential study management component for supporting clinical metabolomics locally at the EPSRC/MRC funded East Midlands Breathomics Pathology Node. Availability and Implementation: LabPipe is freely available to download under a non-commercial open-source license (NPOSL 3.0) along with documentation and installation instructions at http://labpipe.org. Contact: rob.free@le.ac.uk

cs.CE↗

arXiv2011

Phase Separation of Multi-Component Bose-Einstein Condensates of Trapped Atoms and Molecules with a Homonuclear Feshbach Resonance

We investigate phase separation of Bose-Einstein condensates (BECs) of two-component atoms and one-component molecules with a homonuclear Feshbach resonance. We develop a full model for dilute atomic and molecular gases including correlation of the Feshbach resonance and all kinds of interparticle interactions, and numerically calculate order parameters of the BECs in spherical harmonic oscillator traps at zero temperature with the Bogoliubov's classical field approximation. As a result, we find out that the Feshbach resonance can induce two types of phase separation. The actual phase structures and density profiles of the trapped gases are predicted in the whole parameter region, from the atom dominant regime to the molecule dominant regime. We focus on the role of the molecules in the phase separation. Especially in the atom dominant regime, the role of the molecules is described through effective interactions derived from our model. Furthermore we show that a perturbative and semi-classical limit of our model reproduces the conventional atomic BEC (single-channel) model.

cond-mat.quant-gas↗

arXiv2009

Fluctuation properties of strength function associated with the giant quadrupole resonance in 208Pb

We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) giant quadrupole resonance (GQR) in 208Pb where the strength function is obtained by the shell model calculation including 1p1h and 2p2h configurations. It is found that at almost all energy scales, fluctuation of the strength function obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. This is contrasted with the results for the GQR in 40Ca, where at the intermediate energy scale about 1.7 MeV a deviation from the GOE limit was detected. It is found that the physical origin for this different behavior of the local scaling dimension is ascribed to the difference in the properties of the damping process.

nucl-th↗

arXiv2008

p-Wave superfluid and phase separation in atomic Bose-Fermi mixture

We consider a system of repulsively interacting Bose-Fermi mixtures of spin polarized uniform atomic gases at zero temperature. We examine possible realization of p-wave superfluidity of fermions due to an effective attractive interaction via density fluctuations of Bose-Einstein condensate within mean-field approximation. We find the ground state of the system by direct energy comparison of p-wave superfluid and phase-separated states, and suggest an occurrence of the p-wave superfluid for a strong boson-fermion interaction regime. We study some signatures in the p-wave superfluid phase, such as anisotropic energy gap and quasi-particle energy in the axial state, that have not been observed in spin unpolarized superfluid of atomic fermions. We also show that a Cooper pair is a tightly bound state like a diatomic molecule in the strong boson-fermion coupling regime and suggest an observable indication of the p-wave superfluid in the real experiment.

cond-mat.supr-con↗

arXiv2007

Bose-Fermi Pair Correlations in Attractively Interacting Bose-Fermi Atomic Mixtures

We study static properties of attractively interacting Bose-Fermi mixtures of uniform atomic gases at zero temperature. Using Green's function formalism we calculate boson-fermion scattering amplitude and fermion self-energy in the medium to lowest order of the hole line expansion. We study ground state energy and pressure as functions of the scattering length for a few values of the boson-fermion mass ratio $m_b/m_f$ and the number ratio $N_b/N_f$. We find that the attractive contribution to energy is greatly enhanced for small values of the mass ratio. We study the role of the Bose-Fermi pair correlations in the mixture by calculating the pole of the boson-fermion scattering amplitude in the medium. The pole shows a standard quasiparticle dispersion for a Bose-Fermi pair, for $m_b/m_f\geq 1$. For small values of the mass ratio, on the other hand, a Bose-Fermi pair with a finite center-of-mass momentum experiences a strong attraction, implying large medium effects. In addition, we also study the fermion dispersion relation. We find two dispersion branches with the possibility of the avoided crossings. This strongly depends on the number rario $N_b/N_f$.

cond-mat.other↗

arXiv2005

Nodal Domain Distribution for a Nonintegrable Two-Dimensional Anharmonic Oscillator

We investigate the transition from integrable to chaotic dynamics in the quantum mechanical wave functions from the point of view of the nodal structure by employing a two dimensional quartic oscillator. We find that the number of nodal domains is drastically reduced as the dynamics of the system changes from integrable to nonintegrable, and then gradually increases as the system becomes chaotic. The number of nodal intersections with the classical boundary as a function of the level number shows a characteristic dependence on the dynamics of the system, too. We also calculate the area distribution of nodal domains and study the emergence of the power law behavior with the Fisher exponent in the chaotic limit.

nlin.CD↗

arXiv2005

Monopole Oscillations and Dampings in Boson and Fermion Mixture in the Time-Dependent Gross-Pitaevskii and Vlasov Equations

We construct a dynamical model for the time evolution of the boson-fermion coexistence system. The dynamics of bosons and fermions are formulated with the time-dependent Gross-Pitaevsky equation and the Vlasov equation. We thus study the monopole oscillation in the bose-fermi mixture. We find that large damping exists for fermion oscillations in the mixed system even at zero temperature.

cond-mat.soft↗

arXiv2005

Resonant Monopole Oscillation in the Bose-Fermi Mixed System

We study the monopole oscillation in the bose-fermi mixed condensed system by performing the time-dependent Gross-Pitaevskii and Vlasov equations. We study the resonant oscillation where the intrinsic frequencies of boson and fermion oscillations are same.

cond-mat.other↗

arXiv2004

Peierls instability, periodic Bose-Einstein condensates and density waves in quasi-one-dimensional boson-fermion mixtures of atomic gases

We study the quasi-one-dimensional (Q1D) spin-polarized bose-fermi mixture of atomic gases at zero temperature. Bosonic excitation spectra are calculated in random phase approximation on the ground state with the uniform BEC, and the Peierls instabilities are shown to appear in bosonic collective excitation modes with wave-number $2k_F$ by the coupling between the Bogoliubov-phonon mode of bosonic atoms and the fermion particle-hole excitations. The ground-state properties are calculated in the variational method, and, corresponding to the Peierls instability, the state with a periodic BEC and fermionic density waves with the period $π/k_F$ are shown to have a lower energy than the uniform one. We also briefly discuss the Q1D system confined in a harmonic oscillator (HO) potential and derive the Peierls instability condition for it.

cond-mat.mes-hall↗

arXiv2003

Fluctuation properties of strength functions associated with giant resonances

We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) and the isovector (IV) giant quadrupole resonances (GQR) in $^{40}$Ca, where the strength functions are obtained by the shell model calculation within up to the 2p2h configurations. It is found that at small energy scale, fluctuation of the strength function almost obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. On the other hand, we found a deviation from the GOE limit at the intermediate energy scale about 1.7MeV for the IS and at 0.9MeV for the IV. The results imply that different types of fluctuations coexist at different energy scales. Detailed analysis strongly suggests that GOE fluctuation at small energy scale is due to the complicated nature of 2p2h states and that fluctuation at the intermediate energy scale is associated with the spreading width of the Tamm-Dancoff 1p1h states.

nucl-th↗

arXiv2000

Response Function of an Irregular Oscillator

Properties of the response functions for a two-dimensional quartic oscillator are studied based on the diagonalization of the Hamiltonian in a large model space. In particular, response functions corresponding to a given momentum transfer are studied for different values of the coupling parameter in the Hamiltonian. The latter controls regular or chaotic nature of the spectra and eigenstates of the system. Fluctuation properties of the energy-strength correlation of the response are investigated. Even when the statistical properties of the system indicate an almost completely chaotic character, there remains a typical structure in the response function similar to that in the regular system. The nature of this structure is studied in some detail.

chao-dyn↗

arXiv1997

Dissipative Field Theory with Caldeira-Leggett Method and its Application to Disoriented Chiral Condensation

The effective field theory including the dissipative effect is developed based on the Caldeira-Leggett theory at the classical level. After the integration of the small field fluctuations considered as the field radiation, the integro-differential field equation is given and shown to include the dissipative effects. In that derivation, special cares should be taken for the boundary condition of the integration. Application to the linear sigma model is given, and the decay process of the chiral condensate is calculated with it, both analytically in the linear approximation and numerically. With these results, we discuss the stability of chiral condensates within the quenched approximation.

nucl-th↗