Research areas

Our research interest mainly lies in the area of condensed-matter physics and statistical physics. We try to model various many-body phenomena in the nature and analyze the models by means of statistical mechanics, field theory, computer simulations, etc. Abstract models can describe seemingly unrelated phenomena in a unified way; this is the most powerful aspect of statistical physics. The following is a list of research areas in which we are currently working or are planning to work. The list should and will change constantly. We welcome your intersting suggestions.

Non-Hermitian Quantum Mechanics and Localization Phenomena
Although Hamiltonians in quantum mechanics are Hermitian operators, artificial non-Hermitian Hamiltonians can describe physica phenomena effectively. A localization transition of a system with non-Hermitian vector potential and random scalar potential corresponds to a pinning transition of magnetic flux lines in superconductors and provides a novel viewpoint of Hermitian localization.

Conduction of Mesoscopic Systems
Conduction of mesoscopic systems is affected by various elements such as localization and resonance. We are interested in treating the conduction from the point of view of the non-Hermitian quantum mechanics, in particular, the resonant conduction, which has huge peaks in the conductance curve.

Statistical Mechanics of Financial Phenomena
In recent years, there appeared studies that analyzes models of human activities such as financial market price. These studies have great impact on understanding of "many-body" phenomena, which have relied on instinctive skills. In particular, the source of fractal flucutation of stock price is of physical interest.

Statistical Mechanics of Directed Networks
It has benn found that various networks in social systems have a particular aspect of fractal nature. Several models have been proposed to treat such networks statistical mechanically. We are particularly interested in such networks with directed links.