Kita, Takafumi (Publications)

KITA, Takafumi

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Dep. Physics

Hokkaido Univ.

Japanese

2023

T. Kita: J. Phys. Soc. Jpn. 92 (2023) 104401.
Fluctuation Exchange Approximation for Bose-Einstein Condensates
T. Kita: J. Phys. Soc. Jpn. 92 (2023) 054004.
How Infrared Singularities Affect Nambu-Goldstone Bosons at Finite Temperatures

2022

T. Kita: J. Phys. Soc. Jpn. 91 (2022) 114002.
Legendre Transformation of the Luttinger-Ward Functional from the Bare Interaction Vertex to the Renormalized One
M. Ohuchi, H. Ueki, and T. Kita: Phys. Rev. B105 (2022) 064514.
Charging in the vortex lattice of type-II superconductors.

2021

T. Kita: J. Phys. Soc. Jpn. 90 (2021) 024001.
Quantum Field Theory of Correlated Bose-Einstein condensates: I. Basic Formalism.
T. Kita: J. Phys. Soc. Jpn. 90 (2021) 024002.
Quantum Field Theory of Correlated Bose-Einstein condensates: II. Ward-Takahashi Identities and Correlation Functions.

2020

E. S. Joshua, H. Ueki, W. Kohno, and T. Kita: . Phys. Soc. Jpn. 89 (2020) 104702; arXiv:2006.02923.
Zero-Field Surface Charge Due to the Gap Suppression in d-Wave Superconductors.
H. Ueki, H. Morita, M. Ohuchi, and T. Kita: Phys. Rev. B 101 (2020) 184518; arXiv:1903.10733.
Drastic enhancement of the thermal Hall angle in a d-wave superconductor.

2019

T. Kita: J. Phys. Soc. Jpn. 88 (2019) 104003; arXiv:1909.11787.
A Renormalization-Group Study of Interacting Bose-Einstein Condensates:
II. Anomalous Dimension $\eta$ for $d\lesssim4$ at Finite Temperatures.
T. Kita: J. Phys. Soc. Jpn. 88 (2019) 085002.
Specific Heat of Superfluid $^4$He: Why Does It Deviate from the $T^3$ Law at Low Temperatures?
A. Kirikoshi, W. Kohno, and T. Kita: J. Phys. Soc. Jpn. 88 (2019) 064005; arXiv:1905.12211.
Variational Approach to Many-Body Problems Incorporating Many-Body Effects at Finite Temperature
T. Kita: J. Phys. Soc. Jpn. 88 (2019) 054003; arXiv:1903.05230.
A Renormalization-Group Study of Interacting Bose-Einstein Condensates:
Absence of the Bogoliubov Mode below Four (T > 0) and Three (T = 0) Dimensions.

2018

W. Kohno, A. Kirikoshi, and T. Kita: J. Phys. Soc. Jpn. 87 (2018) 124004.
Variational Wave Function for Inhomogeneous Bose-Einstein Condensate with 3/2-Body Correlations.
X. Si, W. Kohno, and T. Kita: J. Phys. Soc. Jpn. 87 (2018) 104703; arXiv:1809.03708.
Number-Phase Fluctuations in Isolated Superconductors.
H. Ueki, M. Ohuchi, and T. Kita: J. Phys. Soc. Jpn. 87 (2018) 044704; arXiv:1801.10390.
Charging in a Superconducting Vortex Due to the Three Force Terms in Augmented Eilenberger Equations.
W. Kohno, A. Kirikoshi, and T. Kita: J. Phys. Soc. Jpn. 87 (2018) 034002; arXiv:1802.04937.
Ground-State Wave Function with Interactions between Different Species in M-Component Miscible Bose-Einstein Condensates.

2017

M. Ohuchi, H. Ueki, and T. Kita: J. Phys. Soc. Jpn. 86 (2017) 073702; arXiv:1706.02449.
Charging due to Pair-Potential Gradient in Vortex of Type-II Superconductors.
T. Kita: J. Phys. Soc. Jpn. 86 (2017) 044003; arXiv:1703.04760.
3/2-Body Correlations and Coherence in Bose-Einstein Condensates.
W. Kohno, H. Ueki, and T. Kita: J. Phys. Soc. Jpn. 86 (2017) 023702; arXiv:1612.08325.
Hall Effect in the Vortex Lattice of d-Wave Superconductors with Anisotropic Fermi Surfaces.

2016

K. Tsutsui, Y. Kato, and T. Kita: J. Phys. Soc. Jpn. 85 (2016) 124004; arXiv:1611.05566.
Are Quasiparticles and Phonons Identical in Bose-Einstein Condensates?
K. Tsutsui and T. Kita: J. Phys. Soc. Jpn. 85 (2016) 114603; arXiv:1610.03617.
Quantum Correlations of Ideal Bose and Fermi Gases in the Canonical Ensemble.
W. Kohno, H. Ueki, and T. Kita: J. Phys. Soc. Jpn. 85 (2016) 083705; arXiv:1607.02807.
Hall Effect in the Abrikosov Lattice of Type-II Superconductors.
H. Ueki, W. Kohno, and T. Kita: J. Phys. Soc. Jpn. 85 (2016) 064702; arXiv:1604.01637.
Vortex-Core Charging Due to the Lorentz Force in a d-Wave Superconductor.

2015

T. Kita: Statistical Mechanics of Superconductivity (Springer, Tokyo, 2015).

2014

T. Kita: J. Phys. Soc. Jpn. 83 (2014) 064005; arXiv:1405.5291.
Effective Action for Bose-Einstein Condensates.
K. Tsutsui and T. Kita: J. Phys. Soc. Jpn. 83 (2014) 033001; arXiv:1402.1196.
Lifetime of Single-Particle Excitations in a Dilute Bose-Einstein Condensate at Zero Temperature.

2013

K. Tsutsui and T. Kita: J. Phys. Soc. Jpn. 82 (2013) 063001; arXiv:1305.0657.
Ground-State Energy and Condensate Density of a Dilute Bose Gas Revisited.

2012

K. Tsutsui and T. Kita: J. Phys. Soc. Jpn. 81 (2012) 114002; arXiv:1210.1620.
Studying Superfluid Transition of a Dilute Bose Gas by Conserving Approximations.

2011

T. Kita: J. Phys. Soc. Jpn. 80 (2011) 124704; arXiv:1111.3431.
Self-Consistent Approximations for Superconductivity beyond the Bardeen-Cooper-Schrieffer Theory.
T. Kita: J. Phys. Soc. Jpn. 80 (2011) 084606; arXiv:1108.2324.
Properties of Nambu-Goldstone Bosons in a Single-Component Bose-Einstein Condensate.

2010

T. Kita: Phys. Rev. B 81 (2010) 214513; arXiv:1006.2161.
Exact results on the two-particle Green's function of a Bose-Einstein condensate.
T. Kita: Prog. Theor. Phys. 123 (2010) 581.
Introduction to Nonequilibrium Statistical Mechanics with Quantum Field Theory.

2009

T. Kita: Phys. Rev. B 80 (2009) 214502; arXiv:0911.3681.
Self-consistent perturbation expansion for Bose-Einstein condensates satisfying Goldstone's theorem and conservation laws.
T. Kita: Phys. Rev. B 79 (2009) 024521; arXiv:0902.0042.
Hall Coefficient of Equilibrium Supercurrents Flowing inside Superconductors.

2008

T. Kita and H. Yamashita: J. Phys. Soc. Jpn. 77 (2008) 024711.
Quantum Transport Equation for Bloch Electrons in Electromagnetic Fields.

2007

T. Kita: J. Phys. Soc. Jpn. 76 (2007) 064006; cond-mat/0705.3926.
Entropy Change through Rayleigh-Béenard Convective Transition with Rigid Boundaries.
Y. Kondo and T. Kita: J. Phys. Soc. Jpn. 76 (2007) 024008; cond-mat/0608472.
Conserving Gapless Mean-Field Theory of a Multi-Component Bose-Einstein Condensate.

2006

T. Kita: J. Phys. Soc. Jpn. 75 (2006) 124005 [erratum: 76 (2007) 038001]; cond-mat/06011271.
Principle of Maximum Entropy Applied to Rayleigh-Bénard Convection.
T. Kita: J. Phys. Soc. Jpn. 75 (2006) 114005 [addenda: 76 (2007) 067001];; cond-mat/06011270.
Entropy in Nonequilibrium Statistical Mechanics.
T. Shibauchi et al.: Phys. Rev. B 74 (2006) 220506(R).
Uncommonly high upper critical field of the pyrochlore superconductor KOs₂O₆ below the enhanced paramagnetic limit.
T. Kita: J. Phys. Soc. Jpn. 75 (2006) 044603; cond-mat/0604241.
Conserving Gapless Mean-Field Theory for Weakly Interacting Bose Gases.

2005

T. Kita and M. Arai: J. Phys. Soc. Jpn. 74 (2005) 2813; cond-mat/0510381.
Theory of Interacting Bloch Electrons in a Magnetic Field.
T. Kita: J. Phys. Soc. Jpn. 74 (2005) 1891; cond-mat/0411296.
Conserving Gapless Mean-Field Theory for Bose-Einstein Condensates.
K. Watanabe, T. Kita and M. Arai: Phys. Rev. B71 (2005) 144515; cond-mat/0501405.
Magnetic-Field Dependence of Thermodynamic Quantities in the Vortex State of Type-II Superconductors.

2004

M. Arai and T. Kita: J. Phys. Soc. Jpn. 73 (2004) 2924; cond-mat/0404628.
Ab Initio Calculations of H_c2 for Nb, NbSe₂, and MgB₂.
T. Kita and M. Arai: Phys. Rev. B70 (2004) 224522; cond-mat/0403314.
Ab Initio Calculations of H_c2 in Type-II Superconductors: Basic Formalism and Model Calculations.
T. Kita: Phys. Rev. B69 (2004) 144507; cond-mat/0311562.
Entropy and Spin Susceptibility of s-Wave Type-II Superconductors near H_c2.
K. Watanabe and T. Kita: J. Phys. Soc. Jpn. 73 (2004) 2239; cond-mat/0401410.
Nonmagnetic Impurity Effects in MgB₂.
T. Kita: J. Phys. Soc. Jpn. 73 (2004) 21; cond-mat/0307067.
Theory of Flux-Flow Resistivity near H_c2 for s-Wave Type-II Superconductors.

2003

T. Kita: Phys. Rev. B68 (2003) 184503; cond-mat/0306231.
Calculation of κ₂(T) for s-Wave Type-II Superconductors.

2002

T. Kita: Phys. Rev. B66 (2002) 224515.
Unconventional vortices and phase transitions in rapidly rotating superfluid ³He.
T. Kita, T. Mizushima, and K. Machida: Phys. Rev. A66 (2002) 061601.
Spinor Bose-Einstein condensates with many vortices.
T. Mizushima, K. Machida, and T. Kita: Phys. Rev. A66 (2002) 053610.
Axisymmetric versus nonaxisymmetric vortices in spinor Bose-Einstein condensates.
K. Yasui and T. Kita: Phys. Rev. B66 (2002) 184516.
Theory of the de Haas-van Alphen effect in type-II superconductors.
T. Kita: J. Phys. Soc. Jpn. 71 (2002) 1795.
On the Density Matrix of Nonequilibrium Steady-State Statistical Matrix.
T. Mizushima, K. Machida, and T. Kita: Phys. Rev. Lett. 89 (2002) 030401.
Mermin-Ho Vortex in Ferromagnetic Spinor Bose-Einstein Condensates.

2001

K. Yasui and T. Kita: J. Phys. Soc. Jpn. 70 (2001) 2852; cond-mat/0103336.
Gap anisotropy and de Haas-van Alphen effect in type-II superconductors.
T. Kita: Phys. Rev. B64 (2001) 054503; cond-mat/0103520.
Gauge invariance and Hall terms in the quasiclassical equations of superconductivity.
T. Kita: Phys. Rev. Lett. 86 (2001) 834.
Vortex-lattice phases of superfluid ³He in rapid rotation.

2000

T. Kita: Physica B 284-288 (2000) 531.
Vortex states of the E_u model for UPt₃.

1999

T. Kita: J. Phys. Soc. Jpn. 68 (1999) 3740.
An exact entropy expression for a many-body problem.
K. Yasui and T. Kita: Phys. Rev. Lett. 83 (1999) 4168; cond-mat/9905067.
Quasiparticles of d-wave superconductors in finite magnetic fields.
T. Kita: Phys. Rev. Lett. 83 (1999) 1846; cond-mat/9905068.
Vortex states of the E_u model for Sr₂RuO₄.

1998

T. Kita: J. Phys. Soc. Jpn. 67 (1998) 2075.
A microscopic theory of Abrikosov lattices: I. Basic formalism.
T. Kita: J. Phys. Soc. Jpn. 67 (1998) 2067.
Solving the Ginzburg-Landau equations with magnetic translation group.
T. Kita: J. Phys. Soc. Jpn. 67 (1998) 216.
Angular momentum of anisotropic superfluids at finite temperatures.

1996

T. Kita: J. Phys. Soc. Jpn. 65 (1996) 1373.
Perturbation expansion for a Fermi superfluid: II. Several equilibrium properties.
T. Kita: J. Phys. Soc. Jpn. 65 (1996) 1355.
Perturbation expansion for a Fermi superfluid: I. Basic formalism and angular momentum.
T. Kita: J. Phys. Soc. Jpn. 65 (1996) 908.
Real-space formalism of the theory of superconductivity.
T. Kita: J. Phys. Soc. Jpn. 65 (1996) 664.
The angular momentum paradox of ³He-A.

1993

T. Kita: J. Phys. Soc. Jpn. 62 (1993) 3539.
Broken time-reversal symmetry of anisotropic superfluidity.
T. Kita: Phys. Rev. B 48 (1993) 3949.
Superconductivity with two critical temperatures.

1991

Y. Takada and T. Kita: J. Phys. Soc. Jpn. 60 (1991) 25.
New self-consistency relation between the correlation energy and the momentum distribution function with application to the one-dimensional Hubbard model.
T. Kita: Phys. Rev. B 43 (1991) 5343.
Magnetic properties of the charged Anderson-Brinkman-Morel State: Absence of H_c1.

1990

T. Kita and Y. Takada: Phys. Rev. A 42 (1990) 3251.
Effective-potential expansion method for the many-body problem at finite temperatures.
II. Application to a one-dimensional electron system with a repulsive delta-function interaction.
Y. Takada and T. Kita: Phys. Rev. A 42 (1990) 3242.
Effective-potential expansion method for the many-body problem at finite temperatures. I. Basic formalism.

1989

T. Kita: Phys. Rev. B 40 (1989) 10816.
Magnetic instability in triplet superconductivity.

1987

T. Kita, K. Ohtaka and Y. Tanabe: J. Phys. Soc. Jpn. 56 (1987) 4609.
Edge singularity and Fano effect in metals.
T. Kita: J. Phys. Soc. Jpn. 56 (1987) 4598.
Higher-order asymptotic expansion for the edge singularities in metals.
T. Kita, K. Ohtaka and Y. Tanabe: J. Phys. Soc. Jpn. 56 (1987) 387.
Core-level X-ray spectra of simple metals: Deviation from the asymptotic theory.

1985

Kita and Y. Tanabe: J. Phys. Soc. Jpn. 54 (1985) 2304.
Ground configuration of spins in GdAlO₃:Cr.
T. Kita and Y. Tanabe: J. Phys. Soc. Jpn. 54 (1985) 2293.
Shapes of R-lines of Cr³⁺ in GdAlO₃.