Let F be a number field and G an even orthogonal or unitary group over a number field. Based on the method used by Gan and Ichino (2018), we prove Arthur’s multiplicity formula for the generic part of the automorphic discrete spectrum of G by using the theta lift. Enhancing this method, we also obtain a description of the full automorphic discrete spectrum of G of F -rank \le1 .

Dissipative state engineering is a general term for a protocol which prepares the ground state of a complex many-body Hamiltonian using engineered dissipation or engineered environments. Recently, it was shown that a version of this protocol, where the engineered environment consists of one or more dissipative qubit ancillas tuned to be resonant with the low-energy transitions of a many-body system, resulted in the combined system evolving to reasonable approximation to the ground state. This potentially broadens the applicability of the method beyond nonfrustrated systems, to which it was previously restricted. Here we argue that this approach has an intrinsic limitation because the ancillas, seen as an effective bath by the system in the weak-coupling limit, do not give the detailed balance expected for a true zero-temperature environment. Our argument is based on the study of a similar approach employing linear coupling to bosonic ancillas. We explore overcoming this limitation using a recently developed open quantum systems technique called pseudomodes. With a simple example model of a one-dimensional quantum Ising chain, we show that detailed balance can be fixed, and a more accurate estimation of the ground state obtained, at the cost of two additional unphysical dissipative modes and the extrapolation error of implementing those modes in physical systems. Published by the American Physical Society 2024

Multiphoton dynamics beyond linear optical materials are of significant fundamental and technological importance in quantum information processing. However, it remains largely unexplored in nonlinear waveguide QED. In this work, we theoretically propose a structured nonlinear waveguide in the presence of staggered photon-photon interactions, which supports two branches of gaped bands for doublons (i.e., spatially bound-photon-pair states). In contrast to linear waveguide QED systems, we identify two important contributions to its dynamical evolution, i.e., single-photon bound states (SPBSs) and doublon bound states (DBSs). Most remarkably, the nonlinear waveguide can mediate the long-range four-body interactions between two emitter pairs, even in the presence of disturbance from SPBSs. By appropriately designing system's parameters, we can achieve high-fidelity four-body Rabi oscillations mediated only by virtual doublons in DBSs. Our findings pave the way for applying structured nonlinear waveguide QED in multi-body quantum information processing and quantum simulations among remote sites. Published by the American Physical Society 2024

Biological age is a construct that seeks to evaluate the biological wear and tear process of the organism that cannot be observed by chronological age. We estimate individuals' biological age based on biomarkers from multiple systems and validate it through its association with mortality from natural causes. Biological age was estimated in 12,109 participants (6621 women and 5488 men) from the first visit of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) who had valid data for the biomarkers used in the analyses. Biological age was estimated using the Klemera and Doubal method. The difference between chronological age and biological age (Δage) was computed. Cox proportional hazard models stratified by sex were used to assess whether Δage was associated with mortality risk after a median follow-up of 9.1years. The accuracy of the models was estimated by the area under the curve (AUC). Δage had equal mean for men and women, with greater variability for men. Cox models showed that every 1-year increase in Δage was associated with increased mortality in men (HR (95% CI) 1.21; 1.17-1.25) and women (HR (95% CI) 1.24; 1.15-1.34), independently of chronological age. Results of the AUC demonstrated that the predictive power of models that only included chronological age (AUC chronological age = 0.7396) or Δage (AUC Δage = 0.6842) was lower than those that included both, chronological age and Δage (AUC chronological age + Δage = 0.802), in men. This difference was not observed in women. We demonstrate that biological age is strongly related to mortality in both genders and is a valid predictor of death in Brazilian adults, especially among men.

While plasma-based accelerators have the potential to positively impact a broad range of research topics, a route to application will only be possible through improved understanding of their stability. We present experimental results of a laser wakefield accelerator in the nonlinear regime in a helium gas jet target with a density transition produced by a razor blade in the flow. Modifications to the target setup are correlated with variations in the plasma density profile diagnosed via interferometry and the shot-to-shot variations of the density profile for nominally equal conditions are characterized. Through an in-depth sensitivity study using particle-in-cell simulations, the effects of changes in the plasma density profile on the accelerated electron beams are investigated. The results suggest that blade motion is more detrimental to stability than gas pressure fluctuations, and that early focusing of the laser may reduce the deleterious effects of such density fluctuations. Published by the American Physical Society 2024

Cleft palatoplasty commonly results in denuded maxillary bone in the lateral gutters and a posterior void between oral and nasal closures. Bony exposure of the anterior palate subjects the maxilla to scarring and growth restriction; scar contracture of the posterior void may result in velopharyngeal insufficiency and fistula formation. Use of the buccal fat pad flap (BFPF) at the time of palatoplasty provides vascularized tissue over these critical areas, thereby reducing the rate of secondary surgery for speech and fistula revision. A single-center, retrospective review identified patients who underwent palatoplasty with or without BFPF between 1995 and 2015. Data collected included cleft type, surgical technique, follow-up duration, and complications. Outcomes included rate of speech surgery and palatal fistula development. Veau phenotype index was computed on a scale of 2 to 4 as a weighted mean to reflect the frequency of cleft type (Veau II through IV) in BFPF and non-BFPF groups. Charts of 866 patients were reviewed; 212 met inclusion criteria. Of these, 101 received a BFPF. Mean follow-up duration was 11.4 years. Despite a selection bias for more severe clefts, the BFPF group had lower incidence of speech surgery (9.9% versus 36.9%; P = 0.0072). The BFPF group had milder cases treatable with fat injection (7.9% versus 2.7%; P = 0.0346) and developed fewer fistulas (6.9% versus 18.0%; P = 0.0280). Despite the presence of more severe clefts, the BFPF group had a significantly lower rate of speech surgery. The BFPF is a valuable adjunct in primary palatoplasty, reducing velopharyngeal insufficiency and fistula formation. Therapeutic, III.

The high sensitivity of the spectrum and wave functions to boundary conditions, termed the non-Hermitian skin effect, represents a fundamental aspect of non-Hermitian systems. While it endows non-Hermitian systems with unprecedented physical properties, it presents notable obstacles in grasping universal properties that are robust against microscopic details and boundary conditions. In this Letter, we introduce a pivotal theorem: in the thermodynamic limit, for any non-Hermitian systems with finite-range interactions, all spectral moments are invariant quantities, independent of boundary conditions, posing strong constraints on the spectrum. Utilizing this invariance, we propose a new criterion for bulk dynamical phases based on experimentally observable features and applicable to any dimensions and any boundary conditions. Based on this criterion, we define the bulk dispersive-to-proliferative phase transition, which is distinct from the real-to-complex spectral transition and contrasts with the traditional expectation that the existence of eigenvalues above the real axis implies proliferative behavior. We verify these findings in 1D and 2D lattice models.

Homodyne detection is used to measure the (collective) atomic dipole moment for an atomic ensemble that is prepared in a superposition of spatially phased Dicke states having at most two excitations (a so-called "superatom"). Homodyne detection allows one to isolate the contributions to the radiated intensity that depend linearly on the average value of the collective atomic dipole moment operator. Depending on whether the atom-reference field interference is constructive or destructive, either super-Poisson or sub-Poisson statistics for the combined field is observed.