# Quantum Physics

**Quest for mysterious quantum world**

Mysterious phenomena appear in the quantum world beyond our ordinary imagination, from elementary particles through atoms, molecules and matter. This quantum world also has intimate relation to the beginning of Universe.

Now, not only understanding this amazing world, but also we are advancing in manipulation and control of quantum phenomena, and developing various applications in our daily life.

## Academic Staff

### Takayuki MIYADERA

Professor (Graduate School of Engineering)

**Research Theme**

Foundations of Quantum Physics, Quantum Information Theory.

**Classes**

Quantum Physics I, Quantum Physics II, Fundamentals of Nuclear Physics, Quantum Field Theory, Advanced Quantum Physics.

**Contact Information**

E-mail: miyadera@deletethis.nucleng.kyoto-u.ac.jp

### Kenzo OGURE

Assistant Professor (Graduate School of Engineering)

**Research Theme**

- Early universe and Particle Physics: Early universe and Particle Physics (Baryogenesis, Dark matter), Finite Temperature Field Theory, Neutrino physics
- Solitons in Field Theory : Topological Soliton, non-Topological Soliton
- Spin Glass and Information Theory: Spin Glass, Replica Method, Application of Statistical Method to Information Theory

**Contact Information**

Katsura Campus, C3 Bldg. d1S02

TEL: +81-75-383-3909

E-mail: ogure@* (Add "nucleng.kyoto-u.ac.jp" after @)

## Research Topics

### Foundations of Quantum Theory

Quantum theory, unlike classical theory, is described in a language that is difficult to understand intuitively. All modern fundamental physics is based on quantum theory, but it has been an open question as to why this quantum theory is correct.

In quantum theory, it is assumed that each system somehow has a Hilbert space associated with it. However, no one has ever seen a Hilbert space floating in the air, we just believe that this is the correct formulation because it has never been wrong. To understand why this argument is so subtle, it helps to contrast it with relativity. In special relativity, the theory was naturally derived from only two principles: the principle of relativity and the principle of invariance of the speed of light. In contrast, quantum theory has not found such a testable principle. Therefore, no matter how many phenomena are verified, it is impossible to convince why quantum theory is correct. My ultimate research goal is to gain a deeper understanding of the nature of quantum theory, and thereby understand why this theory is correct. There are two possible approaches to this goal. One is the approach of looking at quantum theory from the inside. We look at quantum theory from the inside, accepting the axioms of quantum theory and studying what can and cannot be done within these axioms. Another approach is to look at quantum theory from the outside. This approach is to look at quantum theory from the outside, from a broad framework that includes quantum theory, classical theory, and other theories, and to consider how special or not special quantum theory is within that framework.

In the process of seeking a deeper understanding of quantum theory, applications to quantum information are naturally expected. While quantum information, including quantum computer, quantum cryptography and quantum methodology is the most popular field in which quantum properties are used, it is said that quantum theory may also play a role in elucidating life phenomena in the future. I believe that by studying the universal properties of quantum theory, rather than studying specific materials, we will be able to respond to these new developments of the future.