Topological Solitons and Nonperturbative Effects in Field Theory
Project/Area Number  16F16322 
Research Category 
GrantinAid for JSPS Fellows

Allocation Type  Singleyear Grants 
Section  外国 
Research Field 
Particle/Nuclear/Cosmic ray/Astro physics

Research Institution  Keio University 
Host Researcher 
新田 宗土 慶應義塾大学, 商学部(日吉), 教授 (60433736)

Foreign Research Fellow 
CHATTERJEE CHANDRASEKHAR 慶應義塾大学, 自然科学研究教育センター, 外国人特別研究員

Project Period (FY) 
20161107 – 20190331

Project Status 
Granted(Fiscal Year 2017)

Budget Amount *help 
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 2017 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 2016 : ¥500,000 (Direct Cost : ¥500,000)

Keywords  高密度ＱＣＤ / トポロジカル・ソリトン / 渦 / 核物質 / 中性子超流動 / 中性子星 / アリス・ストリング 
Outline of Annual Research Achievements 
1. When a charged particle encircles around an Alice string, it changes the sign of the electric charge. We found a BPSsaturated Alice string in U(1)×SO(3)gauge theory. After performing BPS completion we solved the BPS equations numerically. We further embeded the Alice string into an N=1 supersymmetric gauge theory to show that it is half BPS. 2. Color symmetry is spontaneously broken in quark matter at high density as a consequence of diquark condensations with exhibiting color superconductivity. NonAbelian vortices or color magnetic flux tubes stably exist in the colorflavor locked phase at asymptotically high density. We constructed the effective worldsheet theory of a nonAbelian vortex in regular gauge, confirming the previous results in the singular gauge. As a byproduct of our analysis, we found that nonAbelian vortices in highdensity QCD do not suffer from any obstruction for the global definition of a symmetry breaking. 3. We discussed collective excitations of quantized superfluid vortices in neutron 3P2 superfluids, which likely exist in high density neutron matter such as neutron stars. We found a gapfull mode whose lowenergy description takes the simple form of a double sineGordon model. The associated kink solution and its effects on spontaneous magnetization inside the vortex core were analyzed in detail. 4. We found that a recently proposed interaction involving the vorticity current of electrons, which radiatively induces a photon mass in 3+1 dimensions in the lowenergy effective theory, corresponds to confining strings between electrons.

Current Status of Research Progress 
Current Status of Research Progress
1 : Research has progressed more than it was originally planned.
Reason
今年度は、論文を数本プレプリントではあるが、出している。計画書に書いた、高密度ＱＣＤについては、非アーベリアン渦の有効理論を構築して、論文Phys.Rev. D95 (2017) no.8, 085013を出版した。中性子超流動については、渦の有効理論を構築し、プレプリントではあるが、ePrint: arXiv:1612.05588 [nuclth] を出している。 また、予定していなかった進展として、BPS Aliceストリングを発見し、プレプリントではあるがePrint: arXiv:1703.08971 [hepth]を書いた。

Strategy for Future Research Activity 
1.Alice string: An Alice string has a nontrivial topological property that charged particles flip the sign of the electric charge after encircling the string once, and as a consequence the charge becomes globally undefined. Since the discovery there was no explicit Bogomol'nyiPrasadSommerfield(BPS) or minimum energy construction of Alice string so far. Recently we proposed a BPS construction of Alice string. Alice string contains an U(1) zero mode and we are computing the effective action for the scalar zero mode. There will be fermion zero modes also and we are planing to show an index theorem for Alice string. Our BPS Alice string is a single vortex construction. The next step will be constructing multivortex configurations. We want to generalize the system for SU(N) and SO(N) gauge theories. 2.Dense QCD: Quark matter at high density may exhibit color superconductivity. At asymptotically large density the ground state is found to be the most symmetric threeflavor colorsuperconductivity called the colorflavorlocked(CFL) phase due to the condensation of quarkquark pairing. The physics is under theoretical control in this regime because the QCD coupling constant is weak due to the asymptotic freedom. The breaking of the global baryon number, color and flavor symmetry generates nonAbelian superfluid vortices which carry colormagnetic flux. The situation is dual to hadronic phase. Dual confinement of magnetic monopole by colormagnetic fluxtube has been shown to exist. I would like to analyze tis system closely in the presence of fermions.

Report
(1results)
Research Products
(8results)