Given the huge size of the generic four-dimens-ional scalar potentials arising from the type II supergravities based on toroidal orientifolds, it is even hard to analytically solve the extremization conditions, and therefore the previous studies have been mainly focused on taking some numerical approaches. In this work, using the so-called we demonstrate that the scalar potential and the extremization conditions can be simplified to a great extent, leading to the possibility of performing an analytic exploration of the flux landscape. In this regard, we consider the isotropic case of a type IIB model based on the standard $${\mathbb T}^6/({\mathbb Z}_2 \times {\mathbb Z}_2)$$ orientifold having the three-form fluxes $$F_3/H_3$$ and the non-geometric -flux. This model results in around 300 terms in the scalar potential which depend on 6 moduli/axionic fields and 14 flux parameters. Considering that the axionic flux polynomials can take either zero or non-zero values results in the need of analyzing $$2^{14}=16{,}384$$ candidate configurations, and we find that more than 16,200 of those result in No-Go scenarios for Minkowskian/de-Sitter vacua. Based on our systematic exploration of non-tachyonic flux vacua, we present a detailed classification of such No-Go scenarios as well as the leftover “undecided” configurations for which we could not conclude about the presence/absence of the stable Minkowskian/de-Sitter vacua.

Iran

Shehu AbdusSalam

China

Xin Gao

Greece

George Leontaris

India

Pramod Shukla

Systematic exploration of the non-geometric flux landscape

The Gao-Wald theorem says that the Penrose diagram of de Sitter spacetime reacts to a positive energy perturbation by getting “taller”. How does this change in the presence of timelike boundaries? We study this question in two-dimensional de Sitter JT gravity coupled to conformal matter. The effect of the boundaries has its roots in quantum corrections to the vacuum energy of the CFT due to Casimir-like effects. We consider two different kinds of timelike boundaries, and for each kind we compute the vacuum expectation value of the matter CFT stress tensor. The stress tensor violates the null energy condition in the first case and saturates it in the second case, with each case exhibiting a negative energy density in the vacuum state. We then compute the semiclassical backreaction of this energy density and show how it can make the spacetime “fatter” or “taller” or a combination of both, depending on the regime. The spacetime getting fatter corresponds to an increase in the value of the dilaton at the horizon and hence also in the static patch horizon area in the higher-dimensional solution. We comment on the implications of our results for the quantum theories living on the timelike boundaries.

United States

Gauri Batra

Timelike boundaries in de Sitter JT gravity and the Gao-Wald theorem

Using the Kreuzer-Skarke database of 4-dimensional reflexive polytopes, we systematically constructed a new database of orientifold Calabi-Yau threefolds with h 1,1(X) ≤ 12. Our approach involved non-trivial ℤ2 involutions, incorporating both divisor exchanges and multi-divisor reflections acting on the Calabi-Yau threefolds. Each proper involution results in an orientifold Calabi-Yau threefolds and we constructed 320, 386, 067 such examples. We developed a novel algorithm that significantly reduces the complexity of determining all the fixed loci under the involutions, and clarifies the types of O-planes. Our results show that under proper involutions, the majority of cases end up with O3/O7-plane systems, and most of these further admit a naive Type IIB string vacua. Additionally, a new type of free action was determined. We also computed the smoothness and the splitting of Hodge numbers in the ℤ2-orbifold limit for these orientifold Calabi-Yau threefolds.

Xu Cao

Hongfei Gao

Orientifold Calabi-Yau threefolds: divisor exchanges and multi-reflections

The dark photon is a promising candidate for the dark matter which comprises most of the matter in our visible Universe. Via kinetic mixing with the Standard Model it can also be resonantly converted to photons in an electromagnetic cavity, offering novel experimental possibilities for the discovery and study of dark matter. We report the results of a pathfinder dark photon dark matter cavity search experiment performed at Hunan Normal University and the Institute of Physics, Chinese Academy of Sciences, representing the first stage of the Axion and dark Photon EXperiment program. Finding no statistically significant excess, we place an upper limit on the kinetic mixing parameter <math><mrow><mo>|</mo><mi>χ</mi><mo>|</mo><mo>&lt;</mo><mn>3.7</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>13</mn></mrow></msup></mrow></math> around <math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>A</mi></mrow></msub><mo>≃</mo><mn>29.5</mn><mtext> </mtext><mtext> </mtext><mi>μ</mi><mi>eV</mi></mrow></math> at 90% confidence level. This result exceeds other constraints on dark photon dark matter in this frequency range by roughly an order of magnitude.

Dong He

Jie Fan

Yu Gao

Nick Houston

Zhongqing Ji

Yirong Jin

Chuang Li

Jinmian Li

Tianjun Li

Shi-hang Liu

Jia-Shu Niu

Zhihui Peng

Liang Sun

Zheng Sun

Jia Wang

Puxian Wei

Lina Wu

Zhongchen Xiang

Qiaoli Yang

Chi Zhang

Wenxing Zhang

Xin Zhang

Dongning Zheng

Ruifeng Zheng

Jian-yong Zhou

Dark photon constraints from a 7.139 GHz cavity haloscope experiment

We study a nearly critical superfluid system from two complementary approaches. Within the first approach, we formulate a Schwinger-Keldysh effective field theory (EFT) for the system when it is located slightly above the critical temperature. The dynamical variables in the EFT construction are two scalars: a neutral scalar associated with the conserved U(1) charge, and a complex scalar describing the order parameter. The set of symmetries, particularly the dynamical Kubo-Martin-Schwinger (KMS) symmetry and chemical shift symmetry, strictly constrains the form of EFT action. Within the second approach, using the holographic Schwinger-Keldysh technique, we derive the effective action for a “microscopic” holographic superfluid, confirming the EFT construction. A systematic inclusion of non-Gaussianity is one highlight of present study.

Yanyan Bu

Zhiwei Li

Nearly critical superfluid: effective field theory and holography

Generalized complete intersection Calabi-Yau manifold (gCICY) is a new construction of Calabi-Yau manifolds established recently. However, the standard algebraic method to generate new gCICYs is very laborious. Because of this complexity, the number of gCICYs and their classification still remains unknown. In this paper, we try to make some progress in this direction using neural networks. Our results showed that the trained models cannot only get high accuracy on the type (1, 1) and type (2, 1) gCICYs existing in the literature but also achieve a 97% accuracy in predicting new gCICYs not used in the training. This shows that machine learning is an effective method to classify and generate new gCICY.

Wei Cui

Juntao Wang

Machine learning on generalized complete intersection Calabi-Yau manifolds

To establish metastable de Sitter vacua or even just scale-separated AdS, control over perturbative corrections to the string-derived leading-order 4d lagrangian is crucial. Such corrections can be classified in three types: first, there are genuine loop effects, insensitive to the UV completion of the 10d theory. Second, there are local $\textit{α}$′ corrections or, equivalently, 10d higher-dimension operators which may or may not be related to loop-effects. Third, warping corrections affect the 4d Kahler potential but are expected not to violate the 4d no-scale structure. With this classification in mind, we attempt to derive the Berg-Haack-Pajer conjecture for Kahler corrections in type-IIB Calabi-Yau orientifolds and extend it to include further terms. This is crucial since the interesting applications of this conjecture are in the context of generic Calabi-Yau geometries rather than in the torus-based models from which the main motivation originally stems. As an important by-product, we resolve a known apparent inconsistency between the parametric behaviour of string loop results and field-theoretic expectations. Our findings lead to some interesting new statements concerning loop effects associated with blowup-cycles, loop corrections in fibre inflation, and possible logarithmic effects in the Kahler and scalar potential.

Germany

Arthur Hebecker

Simon Schreyer

Victoria Venken

Loops, local corrections and warping in the LVS and other type IIB models

The large volume scenario (LVS) for de Sitter compactifications of the type IIB string is, at least in principle, well protected from various unknown corrections. The reason is that, by construction, the Calabi-Yau volume is exponentially large. However, as has recently been emphasised, in practice the most explicit models are rather on the border of parametric control. We identify and quantify parametrically what we believe to be the main issue behind this difficulty. Namely, a large volume implies a shallow AdS minimum and hence a small uplift. The latter, if it relies on an anti-D3 in a throat, requires a large negative tadpole. As our main result, we provide a simple and explicit formula for what this tadpole has to be in order to control the most dangerous corrections. The fundamental ingredients are parameters specifying the desired quality of control. We comment on the interplay between our constraint and the tadpole conjecture. We also discuss directions for future work which could lead to LVS constructions satisfying the tadpole constraint with better control, as well as further challenges that may exist for the LVS. Our formula then represents a very concrete challenge for future searches for and the understanding of relevant geometries.

The LVS parametric tadpole constraint

We establish an orientifold Calabi-Yau threefold database for h 1,1(X) ≤ 6 by considering non-trivial ℤ2 divisor exchange involutions, using a toric Calabi-Yau database ( www.rossealtman.com/tcy  ). We first determine the topology for each individual divisor (Hodge diamond), then identify and classify the proper involutions which are globally consistent across all disjoint phases of the Kähler cone for each unique geometry. Each of the proper involutions will result in an orientifold Calabi-Yau manifold. Then we clarify all possible fixed loci under the proper involution, thereby determining the locations of different types of O-planes. It is shown that under the proper involutions, one typically ends up with a system of O3/O7-planes, and most of these will further admit naive Type IIB string vacua. The geometries with freely acting involutions are also determined. We further determine the splitting of the Hodge numbers into odd/even parity in the orbifold limit. The final result is a class of orientifold Calabi-Yau threefolds with non-trivial odd class cohomology (  <math> <msubsup> <mi>h</mi> <mo>−</mo> <mrow> <mn>1</mn> <mo>,</mo> <mn>1</mn> </mrow> </msubsup> </math>  $$ {h}_{-}^{1,1} $$ (X/σ *) ≠ 0).

Ross Altman

Jonathan Carifio

Brent Nelson

Orientifold Calabi-Yau threefolds with divisor involutions and string landscape

We use the machine learning technique to search the polytope which can result in an orientifold Calabi-Yau hypersurface and the “naive type IIB string vacua.” We show that neural networks can be trained to give a high accuracy for classifying the orientifold property and vacua based on the newly generated orientifold Calabi-Yau database with <math><msup><mi>h</mi><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup><mo>(</mo><mi>X</mi><mo>)</mo><mo>≤</mo><mn>6</mn></math> [R. Altman, J. Carifio, X. Gao, and B. Nelson, Orientifold Calabi-Yau threefolds with divisor involutions and string landscape, arXiv:2111.03078]. This indicates the orientifold symmetry may already be encoded in the polytope structure. In the end, we try to use the trained neural networks model to go beyond the database and predict the orientifold signal of polytope for higher <math><msup><mi>h</mi><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup><mo>(</mo><mi>X</mi><mo>)</mo></math>.

Hao Zou

Applying machine learning to the Calabi-Yau orientifolds with string vacua