電子相関と不規則性の共存下における単一粒子励起: Anderson-Hubbard模型の数値研究

Yichen Huang

Abstract It is well known that in Anderson localized systems, starting from a random product state the entanglement entropy remains bounded at all times. However, we show that adding a single boundary term to an Anderson localized Hamiltonian leads to unbounded growth of entanglement. Our results imply that Anderson localization is not a local property. One cannot conclude that a subsystem has Anderson localized behavior without looking at the whole system, as a term that is arbitrarily far from the subsystem can affect the dynamics of the subsystem in such a way that the features of Anderson localization are lost.

T Schork

Kuei Sun, Chiu Ching-Kai, Hsiang-Hsuan Hung +1 more

Sriganapathy Raghav, Barun Halder, Pradosh Basu +1 more

We provide an analytical model to fabricate an exponential localization of a Bose-Einstein condensate under a bichromatic optical lattice. Such localization is famously known as Anderson localization. The degree of localization is investigated using the participation ratio to recognize the laser parameter domain for Anderson localization. The exponential nature of the localization is proved, and we also identify the localization length. The tunneling of an Anderson-localized condensate with time is observed, and the revival phenomenon of Anderson localization is reported. Slowing down of Anderson localization is noticed for higher laser intensity. We also study the dynamical and structural stability of the condensate during Anderson localization, which suggests the preferred values of laser power and the time instance to encounter a minimal mean difference in the presence of noise.

小栗 章, Yoshimichi Teratani

Fuyuki Matsuda, Masaki Tezuka, Norio Kawakami

We consider the one-dimensional (1D) quasiperiodic Anderson-lattice model, which has quasiperiodically ordered impurities. The sites with an f-orbital are ordered as a “Fibonacci word”, one way to form 1D quasiperiodic orderings. To treat the correlation effect precisely, we use the density matrix renormalization group (DMRG) method. We show that the spin correlation function in the quasiperiodic system gives a characteristic pattern. Also, by analyzing the f-electron number and its fluctuation, we find that a valence transition, which usually occurs in the periodic Anderson model when the on-site interorbital interaction is large, is not sharp in the quasiperiodic system. Finally, we discuss the properties of the quasiperiodic Anderson-lattice model, comparing them against the Anderson-lattice model with randomly located f-orbitals. We find that the quasiperiodic Anderson-lattice model has a similar property to the periodic Anderson model for spin correlation, but also has a similar property to the Anderson-lattice model with randomly located f-orbitals for the valence fluctuation.