浅野 雅子氏 （成蹊大）
零質量高階スピン場を持つ拡張された弦の場の理論の構成と解析
弦理論の状態空間をテンソル積して、ある種の条件を課した空間を状態空間に持つような「拡張された弦の場の理論」の自由な作用を構成し、ゲージ対称性およびゲージ固定について議論する。この理論から任意のテンソル表現のゲージ場の共変な作用が系統的に得られ、具体的にいくつかの高階スピンゲージ場の作用を構成する。（M. Asano and M. Kato, NPB877 (2013) 1107 and work in progress.）
Multiloop amplitudes of light-cone gauge superstring field theory in noncritical dimensions
It is possible to define light-cone gauge superstring field theory in noncritical dimensions. These theories can be used to regularize contact term divergences. It has been shown that the on-shell tree amplitudes of critical superstring theory can be reproduced by analytically continuing the number of dimensions to 10 in those of noncritical ones. In this talk, we discuss how we can calculate multiloop amplitudes in the noncritical superstring field theory. (This talk is based on a collaboration with K. Murakami.)
The A∞ structure from the Berkovits formulation of open superstring field theory
When we quantize open string field theory, the structure called A∞ plays a crucial role. However, the Berkovits formulation of open superstring field theory, which is one of the most successful formulations of superstring field theory, is based on the large Hilbert space of the superconformal ghost sector, and we have not been able to see the A∞ structure in this formulation. Recently, on the other hand, Erler, Konopka and Sachs succeeded in constructing an action with the A∞ structure by formulating open superstring field theory based on the small Hilbert space. In this talk, we show that this theory with the A∞ structure is related to the Berkovits formulation by field redefinition and partial gauge fixing. This talk is based on an upcoming paper with Erler and Takezaki.
超弦の場の理論における古典解と数値解析
ここでは、弦場のレベルトランケーション近似を用いて、超弦の場の理論における古典解とそのゲージ不変量の数値的な振る舞いを調べる。これにより、近年可能になってきた解析計算とその物理的解釈の正当化を与え、また、弦場の空間のより深い理解につながると期待している。
Symmetries and Feynman Rules for Ramond Sector in WZW-type Superstring Field Theories
We examine the symmetries of the action supplemented by the constraint in the WZW-type open and heterotic superstring field theories. It is found that these pseudo-actions have additional gauge symmetries provided we impose the constraint after the transformation. Respecting these additional symmetries, we propose a prescription for the new Feynmna rules for the Ramond sector. It is shown that the new rules reproduce the well-known on-shell four- and five-point amplitudes with external fermions.
Closed Superstrings at Finite Temperature in the Framework of Thermo Field Dynamics
Although the finite temperature systems of strings have been mainly examined in the framework of Matsubara formalism, quite a few works have been done to investigate these systems in the framework of thermo field dynamics. Previously we have calculated the thermal vacuum state and the partition function for a single closed superstring in the framework of thermo field dynamics. From this we can reproduce the free energy for multiple strings in the case of Matsubara method. However it is unsatisfactory to derive free energy in such a way, since the free energy for multiple strings should be obtained by only calculating the expectation value of the corresponding operator in the thermal vacuum state. In this talk, we compute the thermal vacuum state for multiple closed superstrings based on free light-cone superstring field theory. From this we can reproduce the free energy for closed superstrings in the case of Matsubara method. We coment on the relation between this closed superstrings at finite temperature and the open superstrings on D9-brane–anti-D9-brane pairs.
WZW-type NS-NS string field theory and its gauge fixing conditions
NS-NS超弦の場の理論に対する Wess-Zumino-Witten型の定式化とそのゲージ固定について議論する。WZW-typeの作用に対する部分ゲージ固定条件として、部分ゲージ固定後の作用が Erler, Konopka, Suchsによって構成された L∞-type の作用と合致するものを探し、WZW型の定式化のゲージ固定を試みる。（arXiv:1407.8485、及び、学位論文に基づく。）
Ramond-Ramond couplings of D-branes
BSFTとよばれる開弦の場の理論では、超開弦の場の理論の作用はディスク分配関数によって与えられると考えられている。我々はRamond- Ramondセクターに対して、任意の境界相互作用を入れた分配関数を局所化の手法によって厳密に計算した。これによってD9ブレーン（あるいはD9-反 D9ブレーン対）上の有質量モードを含む任意のボソン的な超開弦の場とRR場とのカップリング公式を書き下すことができ、それがQuillenの superconnectionを用いて書かれることがわかったので、その結果と応用について議論したい。