Zobrazeno 1 - 10
of 47
pro vyhledávání: '"Umetsu, Koichiro"'
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
The canonical commutation relations in quantum mechanics are not maintained in the anomalous Hall effect described by Berry's phase in the presence of the electromagnetic vector potential. To define quantum mechanical formulation, one may avoid the e
Externí odkaz:
http://arxiv.org/abs/2310.02052
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
Publikováno v:
Progress in Particle and Nuclear Physics (2022)
The basic materials of Berry's phase and chiral anomalies are presented to appreciate the phenomena related to those notions. As for Berry's phase, a general survey of the subject is presented using both Lagrangian and Hamiltonian formalisms. The can
Externí odkaz:
http://arxiv.org/abs/2209.08334
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
A path integral (Lagrangian formalism) is used to derive the effective equations of motion of the anomalous Hall effect with Berry's phase on the basis of the adiabatic condition $|E_{n\pm1}-E_{n}|\gg 2\pi\hbar/T$, where $T$ is the typical time scale
Externí odkaz:
http://arxiv.org/abs/2201.01104
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
Publikováno v:
Phys. Rev. D 103, 096004 (2021)
Berry's phase, which is associated with the slow cyclic motion with a finite period, looks like a Dirac monopole when seen from far away but smoothly changes to a dipole near the level crossing point in the parameter space in an exactly solvable mode
Externí odkaz:
http://arxiv.org/abs/2101.10541
A new approach to the classical limit of Grover's algorithm is discussed by assuming a very rapid dephasing of a system between consecutive Grover's unitary operations, which drives pure quantum states to decohered mixed states. One can identify a sp
Externí odkaz:
http://arxiv.org/abs/1804.10082
Publikováno v:
Annals of Physics 368 (2016) 248
The practically useful criteria of separable states $\rho=\sum_{k}w_{k}\rho_{k}$ in $d=2\times2$ are discussed. The equality $G({\bf a},{\bf b})= 4[\langle \psi|P({\bf a})\otimes P({\bf b})|\psi\rangle-\langle \psi|P({\bf a})\otimes{\bf 1}|\psi\rangl
Externí odkaz:
http://arxiv.org/abs/1603.01792
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
It is generally assumed that {\em local realism} represented by a noncontextual and local hidden-variables model in $d=4$ such as the one used by Bell always gives rise to CHSH inequality $|\langle B\rangle|\leq 2$. On the other hand, the contraposit
Externí odkaz:
http://arxiv.org/abs/1410.1702
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
Publikováno v:
Progress of Theoretical and Experimental Physics 013A03 (2013)
A numerical illustration of a universally valid Heisenberg uncertainty relation, which was proposed recently, is presented by using the experimental data on spin-measurements by J. Erhart, et al.[ Nature Phys. {\bf 8}, 185 (2012)]. This uncertainty r
Externí odkaz:
http://arxiv.org/abs/1211.1828
Autor:
Matsuno, Ken, Umetsu, Koichiro
Publikováno v:
Phys.Rev.D83:064016,2011
We discuss Hawking radiation from a five-dimensional squashed Kaluza-Klein black hole on the basis of the tunneling mechanism. A simple manner, which was recently suggested by Umetsu, is possible to extend the original derivation by Parikh and Wilcze
Externí odkaz:
http://arxiv.org/abs/1101.2091
Autor:
Fujikawa, Kazuo, Umetsu, Koichiro
Publikováno v:
Prog. Theor. Phys. 125 (2011), 205-224
The uncertainty relation and the probability interpretation of quantum mechanics are intrinsically connected, as is evidenced by the evaluation of standard deviations. It is thus natural to ask if one can associate a very small uncertainty product of
Externí odkaz:
http://arxiv.org/abs/1012.1752