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Sorelli, G., Gessner, M., Treps, N., & Walschaers, M. (2024). Gaussian quantum metrology for mode-encoded parameters. New J. Phys., 26(7), 073022–23pp.
Abstract: Quantum optical metrology aims to identify ultimate sensitivity bounds for the estimation of parameters encoded into quantum states of the electromagnetic field. In many practical applications, including imaging, microscopy, and remote sensing, the parameter of interest is not only encoded in the quantum state of the field, but also in its spatio-temporal distribution, i.e. in its mode structure. In this mode-encoded parameter estimation setting, we derive an analytical expression for the quantum Fisher information valid for arbitrary multimode Gaussian fields. To illustrate the power of our approach, we apply our results to the estimation of the transverse displacement of a beam and to the temporal separation between two pulses. For these examples, we show how the estimation sensitivity can be enhanced by adding squeezing into specific modes.
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IDS Collaboration(Andel, B. et al), Algora, A., & Nacher, E. (2024). β decay of the ground state and of a low-lying isomer in Bi-216. Phys. Rev. C, 109(6), 064321–18pp.
Abstract: A detailed beta -decay study of the low- and high -spin states in 216 Bi has been performed at the ISOLDE Decay Station at the CERN-ISOLDE facility. In total, 48 new levels and 83 new transitions in the beta -decay daughter 216 Po were identified. Shell -model calculations for excited states in 216 Bi and 216 Po were performed using the H208 and the modified Kuo-Herling particle effective interactions. Based on the experimental observations and the shell -model calculations, the most likely spin and parity assignments for the beta -decaying states in 216 Bi are (3 – ) and (8 – ), respectively.
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Sanchis-Lozano, M. A., & Sanz, V. (2024). Observable imprints of primordial gravitational waves on the temperature anisotropies of the cosmic microwave background. Phys. Rev. D, 109(6), 063529–11pp.
Abstract: We examine the contribution of tensor modes, in addition to the dominant scalar ones, on the temperature anisotropies of the cosmic microwave background (CMB). To this end, we analyze in detail the temperature two -point angular correlation function C(Theta) from the Planck 2018 dataset, focusing on large angles (Theta greater than or similar to 120 degrees) corresponding to small l multipoles. A hierarchical set of infrared cutoffs are naturally introduced to the scalar and tensor power spectra of the CMB by invoking an extra Kaluza-Klein spatial dimension compactifying at about the grand unified theory scale between the Planck epoch and the start of inflation. We associate this set of lower scalar and tensor cutoffs with the parity of the multipole expansion of the C(Theta) function. By fitting the Planck 2018 data we compute the multipole coefficients, thereby reproducing the well-known odd -parity preference in angular correlations seen by all three satellite missions: Cosmic Background Explorer, WMAP, and Planck. Our fits improve significantly once tensor modes are included in the analysis, hence providing a hint of the imprints of primordial gravitational waves on the temperature correlations observed in the CMB today. To conclude, we suggest a relationship between, on the one hand, the lack of (positive) large -angle correlations and the odd -parity dominance in the CMB and, on the other hand, the effect of primordial gravitational waves on the CMB temperature anisotropies.
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De Romeri, V., Martin Lozano, V., & Sanchez Garcia, G. (2024). Neutrino window to scalar leptoquarks: From low energy to colliders. Phys. Rev. D, 109(5), 055014–21pp.
Abstract: Leptoquarks are theorized particles of either scalar or vector nature that couple simultaneously to quarks and leptons. Motivated by recent measurements of coherent elastic neutrino -nucleus scattering, we consider the impact of scalar leptoquarks coupling to neutrinos on a few complementary processes, from low energy to colliders. In particular, we set competitive constraints on the typical mass and coupling of scalar leptoquarks by analyzing recent COHERENT data. We compare these constraints with bounds from atomic parity violation experiments, deep inelastic neutrino -nucleon scattering and collider data. Our results highlight a strong complementarity between different facilities and demonstrate the power of coherent elastic neutrino -nucleus scattering experiments to probe leptoquark masses in the sub-TeV range. Finally, we also present prospects for improving current bounds with future upgrades of the COHERENT detectors and the planned European Spallation Source.
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Araujo Filho, A. A., Hassanabadi, H., Heidari, N., Kriz, J., & Zare, S. (2024). Gravitational traces of bumblebee gravity in metric-affine formalism. Class. Quantum Gravity, 41(5), 055003–21pp.
Abstract: This work explores various manifestations of bumblebee gravity within the metric-affine formalism. We investigate the impact of the Lorentz violation parameter, denoted as X, on the modification of the Hawking temperature. Our calculations reveal that as X increases, the values of the Hawking temperature attenuate. To examine the behavior of massless scalar perturbations, specifically the quasinormal modes, we employ the Wentzel-Kramers-Brillouin method. The transmission and reflection coefficients are determined through our calculations. The outcomes indicate that a stronger Lorentz-violating parameter results in slower damping oscillations of gravitational waves. To comprehend the influence of the quasinormal spectrum on time-dependent scattering phenomena, we present a detailed analysis of scalar perturbations in the time-domain solution. Additionally, we conduct an investigation on shadows, revealing that larger values of X correspond to larger shadow radii. Furthermore, we constrain the magnitude of the shadow radii using the EHT horizon-scale image of SgrA* . Finally, we calculate both the time delay and the deflection angle.
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