Probing CP violation in photon self-interactions with cavities

In this paper we study CP violation in photon self-interactions at low energy. These interactions, mediated by the effective operator $$ FFF\tilde{F} $$ FFF F ˜ , where ($$ \tilde{F} $$ F ˜ ) F is the (dual) electromagnetic field strength, have yet to be directly probed experimentally. Possible sources for such interactions are weakly coupled light scalars with both scalar and pseudoscalar couplings to photons (for instance, complex Higgs-portal scalars or the relaxion), or new light fermions coupled to photons via dipole operators. We propose a method to isolate the CP-violating contribution to the photon self-interactions using Superconducting Radio-Frequency cavities and vacuum birefringence experiments. In addition, we consider several theoretical and experimental indirect bounds on the scale of new physics associated with the above effective operator, and present projections for the sensitivity of the proposed experiments to this scale. We also discuss the implications of these bounds on the CP-violating couplings of new light particles coupled to photons.

EFT diagrammatica: UV roots of the CP-conserving SMEFT

The Standard Model Effective Field Theory (SMEFT) is an established theoretical framework that parametrises the impact a UV theory has on low-energy observables. Such parametrization is achieved by studying the interactions of SM fields encapsulated within higher mass dimensional (≥ 5) operators. Through judicious employment of the tools of EFTs, SMEFT has become a source of new predictions as well as a platform for conducting a coherent comparison of new physics (beyond Standard Model) scenarios. We, for the first time, are proposing a diagrammatic approach to establish selection criteria for the allowed heavy field representations corresponding to each SMEFT operator. We have elucidated the links of a chain connecting specific CP conserving dimension-6 SMEFT operators with unique sets of heavy field representations. The contact interactions representing each effective operator have been unfolded into tree- and (or) one-loop-level diagrams to reveal unique embeddings of heavy fields within them. For each case, the renormalizable vertices of a UV model serve as the building blocks for all possible unfolded diagrams. Based on this, we have laid the groundwork to construct observable-driven new physics models. This in turn also prevents us from making redundant analyses of similar models. While we have taken a predominantly minimalistic approach, we have also highlighted the necessity for non-minimal interactions for certain operators.

Effective operator bases for beyond Standard Model scenarios: an EFT compendium for discoveries

It is not only conceivable but likely that the spectrum of physics beyond the Standard Model (SM) is non-degenerate. The lightest non-SM particle may reside close enough to the electroweak scale that it can be kinematically probed at high-energy experiments and on account of this, it must be included as an infrared (IR) degree of freedom (DOF) along with the SM ones. The rest of the non-SM particles are heavy enough to be directly experimentally inaccessible and can be integrated out. Now, to capture the effects of the complete theory, one must take into account the higher dimensional operators constituted of the SM DOFs and the minimal extension. This construction, BSMEFT, is in the same spirit as SMEFT but now with extra IR DOFs. Constructing a BSMEFT is in general the first step after establishing experimental evidence for a new particle. We have investigated three different scenarios where the SM is extended by additional (i) uncolored, (ii) colored particles, and (iii) abelian gauge symmetries. For each such scenario, we have included the most-anticipated and phenomenologically motivated models to demonstrate the concept of BSMEFT. In this paper, we have provided the full EFT Lagrangian for each such model up to mass dimension 6. We have also identified the CP, baryon (B), and lepton (L) number violating effective operators.

Size of bulk fermions in the SYK model

The study of quantum gravity in the form of the holographic duality has uncovered and motivated the detailed investigation of various diagnostics of quantum chaos. One such measure is the operator size distribution, which characterizes the size of the support region of an operator and its evolution under Heisenberg evolution. In this work, we examine the role of the operator size distribution in holographic duality for the Sachdev-Ye-Kitaev (SYK) model. Using an explicit construction of AdS2 bulk fermion operators in a putative dual of the low temperature SYK model, we study the operator size distribution of the boundary and bulk fermions. Our result provides a direct derivation of the relationship between (effective) operator size of both the boundary and bulk fermions and bulk SL(2; ℝ) generators.

Technique of suppression of bubble oscillation in marine seismic exploration in shallow water

Also, as electric spark and electrodynamic sources, used mainly in works of the upper part of the section, non-explosive sources, which have become widespread, include pneumatic sources. This type of sources meets all the requirements for geophysical equipment. The main problem of such kind of sources is the presence of intense pulsations, long duration of the emitted signals, as well as not very reliability of some clusters. Especially topical is the problem of pulsations during the shallow water acquisitions. The shallow water depth does not allow to extract the signature acceptable for the construction of the effective operator from the data due to the interference of pulsations from the direct wave with the bottom, and the suppression operator which extracted from the theoretical signature, often gives an unacceptable result. To solve the bubble oscillation problems in shallow-water acquisition, it is proposed to use combined information of bubble oscillation extracted from a direct wave, extracted from bottom reflection, waveform predicting deconvolution and adaptive subtraction algorithms.

On the Neumann Laplacian in nonuniformly collapsing strips

Consider the Neumann Laplacian in the region below the graph of [Formula: see text], for a positive smooth function [Formula: see text] with both [Formula: see text] and [Formula: see text] bounded. As [Formula: see text] such region collapses to [Formula: see text] and an effective operator is found, which has Robin boundary conditions at [Formula: see text]. Then, we recover (under suitable assumptions in the case of unbounded [Formula: see text]) such effective operators through uniformly collapsing regions; in such approach, we have (roughly) got norm resolvent convergence for [Formula: see text] diverging less than exponentially.

Dirichlet Laplacian in a thin twisted strip

Let [Formula: see text] be a two-dimensional, infinite and twisted strip in [Formula: see text]. Consider [Formula: see text] the Dirichlet Laplacian operator in [Formula: see text]. At first, we find the effective operator when the transversal sections of [Formula: see text] tend to zero. Then, assuming that [Formula: see text] is thin enough, we show some situations where the discrete spectrum [Formula: see text] is nonempty; an asymptotic behavior for the eigenvalues is also found. In particular, we study the case where the twisted effect “grows” at infinity.