Masao Hirokawa

Learn More
Introduction s Future real-world computational systems are x Complex • " Non-linear, " or • Undecomposable into " independent " modules x Open and adaptive to real world (i.e., to humans and/or natural systems) • Adaptive to unexpected inputs (in a short period of time) — humans and natural systems are unpredictable because autonomous and nondeterministic.(More)
In the Nelson model particles interact through a scalar massless field. For hydrogen-like atoms there is a nucleus of infinite mass and charge Ze, Z > 0, fixed at the origin and an electron of mass m and charge e. This system forms a bound state with binding energy E bin = me 4 Z 2 /2 to leading order in e. We investigate the radiative corrections to the(More)
We derive a mathematical mechanism of infrared catastrophe from the idea for the proof in [22, 23] and generalize it so that we can apply it to several models in quantum field theory. We define the Carleman operator from the operator-theoretical pull-through formula on ground states. Characterizing infrared catastrophe by the Carleman operator, we study the(More)
We consider two kinds of stability (under a perturbation) of the ground state of a self-adjoint operator, being concerned with (i) the sector to which the ground state belongs and (ii) the uniqueness of the ground state. As an application to the Wigner-Weisskopf model which describes one mode fermion coupled to a quantum scalar eld, we prove in the massive(More)
according to Part I of the By-Laws we announce a meeting of the IAMP General Assembly. It will convene on Monday August 3 in the Meridian Hall of the Clarion Congress Hotel in Prague opening at 8pm. The agenda: 1) President report 2) Treasurer report 3) The ICMP 2012 a) Presentation of the bids b) Discussion and informal vote 4) General discussion It is(More)
according to Part I of the By-Laws we announce a meeting of the IAMP General Assembly. It will convene on Monday August 3 in the Meridian Hall of the Clarion Congress Hotel in Prague opening at 8pm. The agenda: 1) President report 2) Treasurer report 3) The ICMP 2012 a) Presentation of the bids b) Discussion and informal vote 4) General discussion It is(More)
This paper addresses the infrared (IR) catastrophe appearing in quantum field theory. IR catastrophe is formulated and studied in operator theory, characterized by the Carleman operator. The theory presented in this paper is applied to the Hamiltonian of the model describing a non-relativistic electron coupled with a quantum field of phonons or polaritons(More)