Shu Tanaka

Quantum response to time-dependent external field (2008)

Miyashita, Seiji, Tanaka, Shu, De Raedt, Hans, Barbara, Bernard

Recently, explicit real time dynamics has been studied in various systems. These quantum mechanical dynamics could provide new recipes in information processing. Here, we study quantum dynamics under...

Slow Relaxation due to Entropy Effect -- Entropic Slowing Down -- (2007)

Tanaka, Shu, Miyashita, Seiji

We study entropic slowing down in a decorated bond system. Though it is commonly known that complicate energy landscape in random spin systems causes slow relaxation, we find that the slowing down...

Slow Relaxation of Spin Structure in Exotic Ferromagnetic Phase of Ising-like Heisenberg Kagome Antiferromagnets (2007)

Tanaka, Shu, Miyashita, Seiji

In the corner-sharing lattice, magnetic frustration causes macroscopic degeneracy in the ground state, which prevents systems from ordering. However, if the ensemble of the degenerate configuration...

Non-monotonic Relaxation in Systems with Reentrant Type Interaction (2007)

Miyashita, Seiji, Tanaka, Shu, Hirano, Masaki

Recently, interesting non-monotonic time evolution has been pointed out in the experiments by J\"onsson, {\it et al.} and Jonsson {\it et.al.} and also in the numerical simulation by Takayama and...

Slow Relaxation Process in Ising like Heisenberg Kagome Antiferromagnets due to Macroscopic Degeneracy in the Ordered State (2006)

Tanaka, Shu, Miyashita, Seiji

We study relaxation phenomena in the ferromagnetically ordered state of the Ising-like Heisenberg kagome antiferromagnets. We introduce the "weathervane loop" in order to characterize macroscopic...

Quantum Annealing Effect on Entropic Slowing Down in Frustrated Decorated Bond System (2006)

Tanaka, Shu, Miyashita, Seiji

We propose that the importance of the quantum annealing procedure to find the ground state of frustrated decorated bond systems where 'entropic slowing down' happens due to peculiar density of...

Electron localization/delocalization in incommensurate helical magnets (2006)

Tanaka, Shu, Katsura, Hosho, Nagaosa, Naoto

The electronic states in incommensurate (IC) helical magnets are studied theoretically from the viewpoint of the localization/delocalization. It is found that in the multi-band system with...

Dynamical properties of temperature chaos and memory effect (2005)

Tanaka, Shu, Miyashita, Seiji

In the frustrated interaction systems, the nature of ordered configuration can be intrinsically temperature dependent. There, the idea of effective coupling of decorated and frustrated bond plays an...