Study of Planck scale space-times via an effective gravity theory in the microscopic regime

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14294
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Kitasato University
• Principal Investigator: Sasaki Shin 北里大学, 理学部, 講師 (20622509)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: Double Field Theory / 超弦理論 / Worldsheet instantons / Algebroid

Outline of Final Research Achievements

It is widely believed that the most promising candidate of consistent quantum gravity is string theory. In string theory ,space-time is probed by a string with finite length. The nature of space-time is, therefore, expected to be quite different from that of Einstein's general relativity.
The purpose of this proposal is to study a characteristic nature of string space-time geometry via the recently formulated double field theory (DFT). The followings are the results in this proposal.
(1) We have found five-brane geometries in heterotic theories that inherit the effects of winding strings in compact space-times. (2) We have found new classical solutions to DFT that encompass string winding effects. The winding corrections to space-times are interpreted as worldsheet instanton effects. (3) We have constructed new gauged linear sigma models which is necessary to calculate the worldsheet instantons. (4) We have studied a nature of algebroids that appear in the doubled geometry of DFT.

Free Research Field

超弦理論

Academic Significance and Societal Importance of the Research Achievements

万物をプランク長程度の弦で説明する超弦理論では時空間を有限長の弦でプローブする。そのため、超弦理論では、アインシュタインの相対性理論とは異なった観点から時空間を扱っている。そのもっとも顕著な例が弦の「巻きつき(winding)」に由来する、従来の時空構造の修正である。本研究では超弦理論に立脚する新しい重力理論「Double Field Theory (DFT)」を具体的に解くことで、時空間への弦の「巻きつき」による効果を調査した。この結果により、超弦理論に特有の時空構造の一旦が明らかになり、従来のアインシュタイン理論では扱えない、プランクスケールの時空描像の理解が進んだ。