# KEK Theory workshop 2018

17-20 December 2018
Kenkyu-Honkan bldg. 1F
Japan timezone
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# Short talks

## Place

Location: Kenkyu-Honkan bldg. 1F
Room: Kobayashi Hall
Date: from 17 Dec 16:20 to 19 Dec 12:15

## Conveners

• 17 Dec 16:20 - 17:50
• Nishinaka Takahiro, Chair:
• 18 Dec 15:50 - 17:35 Short talks
• Isono Hiroshi, Chair:
• 19 Dec 11:30 - 12:15 Short talks
• Ohashi Keisuke, Chair:

## Timetable | Contribution List

Displaying 16 contributions out of 16
Session: Short talks
We revisit CFTs by studying those on curved metric spaces, both orientable and unorientable possibly with boundaries.
Presented by Dr. Ken KIKUCHI on 18/12/2018 at 7:05
Session: Short talks
An idea to formulate string theory or M-theory by a gauge theory attracts theorists and has been extensively studied. The gauge theory should be lower dimensional so that a geometry in string or M-theory, which has higher dimensions, must emerge from it. This suggests that there would be a phase transition in the gauge theory and that the geometry should appear as its temperature decreases. In thi ... More
Presented by Dr. Yuhma ASANO on 18/12/2018 at 7:35
Session: Short talks
In the expanding universe, two interacting fields are no longer in thermal contact when the interaction rate becomes smaller than the Hubble expansion rate. After decoupling, two subsystems are usually treated separately in accordance with equilibrium thermodynamics and the thermodynamic entropy gives a fiducial quantity conserved in each subsystem. In this paper, we discuss a correction to this p ... More
Presented by Dr. Noburo SHIBA on 18/12/2018 at 8:20
Session: Short talks
We propose that the fracton topological order is a class of toy models for holography. The discovery of AdS/CFT correspondence as a concrete construction of holography, and the subsequent developments including the Ryu-Takanayagi formula of entanglement entropy have revolutionized our understanding of quantum gravity, and provided a powerful tool set for solving various strongly-coupled quantum fi ... More
Presented by Mr. Han YAN on 19/12/2018 at 2:45
Session: Short talks
O(α') corrections in 10D heterotic supergravity are known to give nontrivial contributions compared to its type IIA/IIB counterparts. By using a conformal factor ansatz that is valid only for geometries of 2 complex (4 real) dimensions, we obtained a closed expression for the metric correction in the case of several orbifold limits of K3, namely T^4/Z_n where n=2,3,4,6. Furthermore, we numericall ... More
Presented by Mr. Hon Yin LEUNG on 17/12/2018 at 8:20
Session: Short talks
We investigate three-form gauge theories with higher derivative interactions and their supersymmetric extensions in four space-time dimensions. For the bosonic three-form gauge theories, we show that derivatives on the field strength of the 3-form gauge field yield a tachyon as far as the Lagrangian contains a quadratic kinetic term, while such the term with opposite sign gives rise to a ghost. We ... More
Presented by Ryo YOKOKURA on 18/12/2018 at 8:05
Session: Short talks
We discuss a scenario that the dark matter fluid in late time universe emerges as part of the holographic stress-energy tensor on the hypersurface in higher dimensional flat spacetime. We construct a toy model with the Friedmann-Lemaitre-Robertson-Walker (FLRW) hypersurface as the holographic screen in the flat bulk. After adding the baryonic matter on the screen, we assume that both of the dark m ... More
Presented by Dr. Yun-Long ZHANG on 17/12/2018 at 7:50
Session: Short talks
New inflationary models in supergravity with the Dirac-Born-Infeld type kinetic terms and new Fayet-Iliopoulos-type terms are constructed. These models can be considered as the string-inspired deformations of Starobinsky inflationary model in supergravity. Their phenomenological applications are briefly discussed.
Presented by Prof. Sergey KETOV on 19/12/2018 at 3:00
Session: Short talks
IKKT model was proposed as a non-perturbative formulation of superstring theory. We propose a Dirac operator on the noncommutative torus, which is consistent with IKKT model, based on noncommutative geometry. In addition, we consider zero-mode equations of our Dirac operator with magnetic fluxes. We find that zero-mode solutions have chirality and generation structures similar to the commutative c ... More
Presented by Mr. Masaki HONDA on 18/12/2018 at 7:20
Session: Short talks
Let us consider Lovelock theory of gravity in higher dimensional spacetime and compactify extra dimensions with a variety of symmetric Riemann manifolds. In those cases, stability of size moduli of such internal spaces need non-vanishing higher-order Lovelock terms higher than the quadratic term. That is, a dimension of the internal space must be larger than or equal to six.
Presented by Dr. Keisuke OHASHI on 17/12/2018 at 7:35
Session: Short talks
We propose a new mechanism of (geometric) moduli stabilisation in type IIB/F-theory four-dimensional compactifications on Calabi–Yau manifolds, in the presence of 7-branes, that does not rely on non-perturbative effects. Complex structure moduli and the axion-dilaton system are stabilised in the standard way, without breaking supersymmetry, using 3-form internal fluxes. Kähler class moduli stab ... More
Presented by Mr. Yifan CHEN on 17/12/2018 at 7:20
Session: Short talks
We study operator entanglement measures of the unitary evolution operators of (1+1)-dimensional conformal field theories, aiming to uncover scrambling and chaotic behaviors thereof. In particular, we compute the bi-partite and tri-partite mutual in- formation for various configurations of input and output subsystems, and as a function of time. We contrast three different conformal field theories: ... More
Presented by Dr. Masahiro NOZAKI on 19/12/2018 at 2:30
Session: Short talks
We study a direct flux breaking scenario in all three heterotic string theroies on general Calabi-Yau (CY) threefolds. We show background independent formulae to construct three-generation models without chiral exotics from $SO(32)$, $SO(16)\times SO(16)$ and $E8\times E8$ heterotic string theories. In this talk, we show the algorithms to search the formulae and a concrete three-generation model o ... More
Presented by Mr. Kenta TAKEMOTO on 17/12/2018 at 8:35
Session: Short talks
We explore a C-theorem in defect conformal field theories (DCFT) that unify all the known conjectures and theorems until now. We examine as a candidate C-function the additional contributions from conformal defects to the sphere free energy and the entanglement entropy across a sphere in a number of examples including holographic models. We find the two quantities are equivalent, when suitably reg ... More
Presented by Dr. Kento WATANABE on 18/12/2018 at 7:50
Session: Short talks
In supersymmetric theories, the signs of quartic terms in the Kähler potential control the stability of non-supersymmetric field configurations. In particular, in supersymmetric inflation models, the signs are important for the stability of an inflationary trajectory as well as for the prediction of the spectral index. In this paper, we clarify what properties of a UV theory determine the ... More
Presented by Dr. Takahiro TERADA on 17/12/2018 at 8:05
Session: Short talks
Recently, techniques of Yang-Baxter deformation have been developed to study deformations of string sigma model. The deformation can be regarded as the deformation of the target space, and the deformed background always satisfies the (generalized) supergravity equations of motion. We show that the (homogeneous) YB deformations are a kind of local O(d,d) transformation and discuss its generalizatio ... More
Presented by Dr. Yuho SAKATANI on 18/12/2018 at 6:50
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