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We are developing a new problem-solving methodology based on a self-organization paradigm. To realize our future goal of self-organizing computational systems, we have to study computation based on local information and its emergent behavior, which are considered essential in self-organizing systems. This paper presents a stochastic (or nondeterministic)… (More)

- Masao Hirokawa
- 2003

We study the infrared catastrophe for Nelson's Hamiltonian, which has the external potential in a general class. We show that both, the divergence of the total number of soft photons and non-existence of any ground state, are due to the common reason under general conditions.

- Masao Hirokawa, Fumio Hiroshima, Herbert Spohn, Hiroshi Ezawa, Elliott H Lieb, Edward J Nelson
- 2008

We consider a massless scalar Bose field interacting with two particles, one of them infinitely heavy. Neither an infrared nor an ultraviolet cutoff is imposed. In case the charge of the particles is of the same sign and sufficiently small, we prove the existence of a ground state.

- Christian Hainzl, Masao Hirokawa, Herbert Spohn
- 2008

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)

- Asao Arai, Masao Hirokawa, Fumio Hiroshima
- 2008

Regularities and higher order regularities of ground states of quantum field models are investigated through the fact that asymptotic annihilation operators vanish ground states. Moreover a sufficient condition for the absence of a ground state is given.

- Masao Hirokawa
- 2004

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)

- Pavel Exner, Jan Philip Solovej, Valentin A Zagrebnov, Rafael Benguria, Evans Harrell, Masao Hirokawa +6 others
- 2015

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)

- P Exner, M Hirokawa, O Ogurisu
- 1999

We consider a two-dimensional electron with an anomalous magnetic moment, g > 2, interacting with a nonzero magnetic field B perpendicular to the plane which gives rise to a flux F. Recent results about the discrete spectrum of the Pauli operator are extended to fields with the O(r −2−δ) decay at infinity: we show that if |F | exceeds an integer N , there… (More)

- Asao Arai, Masao Hirokawa
- 1999

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)

- Pavel Exner, Jan Philip Solovej, Valentin A Zagrebnov, Rafael Benguria, Evans Harrell, Masao Hirokawa +4 others
- 2014

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)