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Topic Name: Beginning of the “strong power” where it is in the atomic nucleus
Category: Quantum Computing
Research persons: N. Ishii and S. Aoki and T. Hatsuda,
Location: Phys. Dep., Univ. of Tokyo ,Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Japan
Details
As many as 70 years or more before, the Yugawa Hideki doctor *1 in order for
proton and the neutron are restrained “strong power” (the nuclear forces) to
explain in the atomic nucleus, introduced the Yugawa meson which is the unknown
particle. After that, as for the proton neutron meson and the like, doing from
the elementary particle which is called the quark *2 was ascertained
experimentally. But, because of complexity of the quantum color dynamic *3 which
is fundamental theory of the quark, the thing which elucidates the beginning of
the nuclear forces from the quark was in quite difficult circumstance.
The research group of Professor the Ishii reason learning/repairing research
worker of Professor and calculation scientific research center Sinya Aoki of
Tsukuba university graduate school mathematical physical scientific postgraduate
course and first rice field Tetsuo of the University of Tokyo graduate school
science type postgraduate course being joint, by the fact that it does the
large-scale numerical simulation which uses the high-speed super computer “[burujin]”
*5 of high energy accelerator research mechanism on the basis of the technique
which is called the lattice gauge theoretical *4, succeeded in elucidating the
beginning of the nuclear forces from quantum color dynamics for the first time
in the world. The meson theory of Doctor Hideki Yugawa the quark it was verified
not only, it becomes stability of the atomic nucleus and the key to
understanding of structure of the neutron star *6 in the foundation, the
repulsive force core where the nuclear forces are strong was led theoretically.
As the new field, as for this research, physical research which is based on the
quark is opened, it means also to give the theoretical support of the hyper
atomic nucleus *8 formation experiment in the large strength proton accelerator
facility J-PARC*7 which is in the midst of constructing in Ibaraki prefecture
Tokai village. This research result is published to 2007 June edition of the
physical review letter magazine of the American American Institute of Physics.
Background
Doctor Hideki Yugawa (1949 Nobel physics prize prize winning, this year birth
hits), about the meson theory which we assume that the proton which has positive
charge and the neutron which does not have electric charge inside the atomic
nucleus are restrained “strong power” (the nuclear forces) can explain,
theoretically with exchange of the Yugawa meson was lectured in 100. As for this
idea, the power which works between the particles which have the electric charge
like the electron, being able to understand as exchange of the photon it is
something which is conceived in hint. After that the nuclear forces at long
distance are gravitation, with experiment, but at close range it understood that
it becomes strong repulsive force. This is called the repulsive force core of
the nuclear forces. With favor of this repulsive force core, proton and the
neutron do not get near too much, the atomic nucleus is maintained relatively
low at density. In addition, the neutron star which has the weight of 1~2 two
times the solar mass, not collapsing by self gravity is favor of the repulsive
force core. Furthermore, it is thought that also the fact that it becomes cause
of priming of that explosion at the time of II type supernova exploding which
the large mass star pulls up, is the repulsive force core.
Well, as for proton and the neutron it understood due to the development of
high-energy physics ever since Yugawa doctor, that it is restraint state of
three quarks. Therefore, you understand the nuclear forces at the kind of close
range proton and the neutron to be piled up mutually, the quantum color dynamics
which is the theory which controls the quark must be used. Quantum color
dynamics is the theory which designates the gluon which is the quark and the
gauge particle as the basis, but because the gluon does complicated interaction,
it is not possible in even independent proton and the calculation of mass of the
neutron to do easily. Therefore, even strong power and among them it works
between proton and the neutron the repulsive force core as for guiding
theoretically from quantum color dynamics, it was one of the big unsolved
problems in elementary particle atomic nucleus physics.
Lattice gauge theory and high-speed super computer
As the method of making the complicated calculation of quantum color dynamics
possible the fact that it is lectured Doctor [ken] Wilson (1982 Nobel physics
prize prize winning) by, is lattice gauge theory. This quantum color dynamics is
not between continual 4 dimensional space-time, being something which is
constructed in the discrete 4 dimensional lattice space, it is suitable for the
large-scale numerical simulation which used the computer. Recently, precision
calculation of mass of proton and the neutron, with this kind of technique
became possible. Japan is worldwide middle of the target of the lattice gauge
theoretical research which lines up with America and Europe, 2 names especially
of the latest research team (Aoki, Ishii) the Tsukuba university calculation
scientific research center which is related has listed many worldwide research
results.
This time, the research team of the Tsukuba university and the University of
Tokyo applied this lattice gauge theory to the problem of the nuclear forces,
tackled understanding the structure with large-scale numerical simulation. The
enormous calculation which is favored and necessary by the fact that the
up-to-date high-speed super computer “[burujin]” which is introduced into high
energy accelerator research mechanism into the March last year is used became
possible.
Main result
Figure 1, in the origin of the approximate method which is called quench
approximation, large-scale numerical simulation of lattice gauge theory is one
example of the result of doing. Vis-a-vis various protons and the distance of
the neutron, potential energy between proton and the neutron is plotted, (the
red circle). If of potential energy is thought like the slope, with the
direction where the direction where the ball which is placed on the slope rolls
works power, size of inclination of the slope becomes strength of power. The
fact that it is written in the solid line is the potential energy which it
occurs by the fact that Yugawa meson one Doctor Yugawa predicts is exchanged.
Our theoretical calculations with long way have shown the fact that
understanding of the nuclear forces which Doctor Yugawa lectures is correct. As
for this, after the lecturing the Yugawa meson theory which passes 72 years, has
meant the fact that it is verified for the first time from quantum color
dynamics. Furthermore, when proton and the neutron get near to the distance of
10-13cm, with just exchange one of Yugawa mesons when the gravitation which
cannot be explained working, it gets near to close range more, the repulsive
force whose several dozen times that gravitation are strong working you
understand. In other words, the repulsive force core of the nuclear forces, it
is the case that in the world it is guided for the first time from the quark.
The result we obtaining agrees with the various characters of the nuclear forces
which are verified experimentally qualitatively well.
Meaning
In the latest research it became clear, the fact that is related at fact and the
close range the 斥 [ke] it meets, proton and the neutron to pull at long
distance, closely with the basic reason of stability of the atomic nucleus which
is the aggregate of the proton neutron. In addition, existence of the repulsive
force core at close range, gives big impact to research of internal constitution
of the neutron star which is the enormous atomic nucleus which floats in outer
space and priming cause elucidation of supernova explosion. Furthermore, the
latest research by the fact that it expands in interaction of the hyperon and
proton and the neutron which include the strange quark, the strange atomic
nucleus which is planned with the large-sized proton accelerator facility J-PARC
which is in the midst of constructing in Ibaraki prefecture Tokai village (the
hyper atomic nucleus) it is possible also to give the theoretical guide for
synthesis experiment.
As for the repulsive force core existing universally? What essential mechanism
which produces the repulsive force core as for? And so on vis-a-vis problem, if
it is possible to reply theoretically with our methods, finally “as for the
baryon substance of outer space why being able to exist in stability?”Perhaps
with it is answered to the ultimate question which is said.
<< Glossary >>
Doctor Hideki *1. Yugawa: You lecture about the meson theory of the nuclear
forces in 1935 and predicting the pion. Being awarded 1949 Nobel physics prize.
This year it hits birth in 100 of Doctor Yugawa.
*2. quark The base element which forms the substance. The flavor of 6 types
(rise and down, strange, the charm, the bottom and the top) with it has the
color electric charge of 3 types. Proton and the neutron do, the rise quark and
the down quark getting together three.
*3. quantum color dynamics: The basic theory which controls the gluon which
bears the power between the quark, and the quark. Doctor southern Yoichiro (the
University of Chicago) about the prototype was lectured. Gross, Will check, 3
doctors of the poly- czar discovered the asymptotic free characteristic which is
important character of quantum color dynamics (the phenomenon where the extent
interaction which becomes high energy becomes weak) theoretically, were awarded
the Nobel physics prize 2004.
*4. lattice gauge theory: Gauge theory such as quantum color dynamics,
introducing the super cubic lattice into space-time, the theory which it
formulates. It is suitable for the large-scale numerical simulation of the gauge
theory which used the Monte Carlo analysis and the like.
*5. [burujin]: Name of the super computer of IBM. The fact that it is introduced
into high energy accelerator research mechanism into the March last year, with
“IBM System Blue Gene Solution”, is the domestic most fast class type of prime
minister theory operational efficiency 57.3TFlops.
*6. neutron star: Diameter approximately 10km, as for weight 1-2 with the high
density celestial body of times that solar mass, inside has become the liquid of
the neutron mainly. After the large mass star causes supernova explosion, it is
thought that it remains.
*7.J-PARC: In Ibaraki prefecture Naka Gun Tokai village, high energy accelerator
research mechanism and the Japanese atomic energy development research mechanism
being joint, the facility which centers the large strength proton accelerator
which is in the midst of constructing. It is used for the research of various
science and engineering with work schedule, from 2008.
*8. hyper atomic nucleus: The hyperon which includes the strange quark in the
usual atomic nucleus which consists of proton and the neutron, mixed is the new
atomic nucleus.
About Researchers-
T. Hatsuda
e-mail:
hatsuda@phys.s.u-tokyo.ac.jp
Phone, FAX:
+81-3-5841-4123 (tel): +81-3-5841-4224 (fax)
Address:
Phys. Dep., Univ. of Tokyo
Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
S.Aoki
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
TEL: +81-3-3812-2111
Dissertation information >>
N. Ishii and S. Aoki and T. Hatsuda, “Nuclear Force from Lattice QCD” and
Physical Review Letters (2007) in June 29th number publication schedule (as for
electronic edition release schedule June 25th).
<< Reference material >>
Frank [uirutsuetsuku] doctor (2004 Nobel physics prize prize-winner) by “new
fact in January 11 of the nature magazine is published to the commentary
repulsive force core” of our research results which are.
F. Wilczek, “Hard-core revelations” and Nature 445,156-157 (2007)
In The Images-
T. Hatsuda & The form of the nuclear forces which are for the first time obtained in the world making use of the super computer (the red circle). As for prediction of Yugawa meson theory, blue solid line. As for the typical figure in the figure, proton and the neutron which consist of quark three, at long distance exchange the pion, at close range have shown the fact that directly, it is to cause power
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