Institute for Research in Fundamental Sciences

Time-differential perturbed angular correlation (TDPAC) spectroscopy is a nuclear solid-state technique that requires high energy and coincidence-time resolutions from scintillation crystals and photodetectors. Traditionally, photomultiplier tubes (PMTs) have been coupled to LaBr 3 :Ce crystals; however, they have been replaced by Multi Pixel Photon Counters (MPPCs) for TDPAC experiments conducted under external magnetic fields. In this report, we show that, for TDPAC spectroscopy, the performance of the LaBr 3 :Ce-MPPC detector remains stable under magnetic fields up to 8.5 T (in 1 T steps), as evidenced by the unchanged energy and coincidence-time resolutions of the 511 keV peaks from positron–electron (e + -e - ) annihilation in a sealed 22 Na calibration source.

Through 3D hydrodynamical simulations, we explore the impact of Type Ia supernova (SN) explosions on the star formation history and chemical properties of second-generation (SG) stars in young globular clusters with masses of 10 5 −10 6 M ⊙ . We assume that the SG is formed out of the asymptotic giant branch (AGB) ejecta of first-generation stars plus pristine interstellar medium gas which is modelled as a uniform gas moving at a constant velocity towards the cluster. We tested two values for the infalling gas density of 10 −24 and 10 −23 g cm −3 . Type Ia SNe start to explode together with the release of gas from the most massive AGB stars. Three simulated models are analysed. In the low-mass and low-density scenario, we find SNe Ia quench star formation that however restarts when the gas cools down again in between two explosions. The SG stars are dominated by a He-rich population ( Y > 0.33), which is poorly diluted by pristine gas. In the high-mass models, star formation is mildly affected, while the He composition is significantly altered as exploding SNe prevent the accretion of pristine gas, and therefore extremely helium-rich stars form. In the high-density model, such weak gas accretion leads to a maximum enhancement in the helium mass fraction that is much larger than the observed one and that does not correlate with the initial cluster mass as is found in models without Type Ia SNe. As for the iron content, small spreads have been found in all models, but the SG is less homogeneous than the FG, at variance with current observations.

ABSTRACT We investigate relaxation‐order inversion, known as the quantum Mpemba effect (QME), in a minimal open many‐body system called a one‐dimensional four‐site Bose–Hubbard chain governed by Lindblad dynamics with local number dephasing. Families of thermal initial states are prepared at a fixed temperature and evolved under a common reference Liouvillian toward the same stationary state. Relaxation is characterized using four complementary diagnostics: trace distance, quantum relative entropy, symmetry‐projected entropy imbalance (entanglement asymmetry), and the ‐norm of coherence in the Fock basis. We find that QME emerges robustly in ‐the clean interacting regime, where on‐site interactions redistribute the overlaps of initial states with slow Liouvillian decay modes, enabling states initially farther from equilibrium to converge faster at late times. In contrast, the noninteracting limit exhibits a monotonic relaxation hierarchy across all metrics. Introducing a linear Stark potential or random on‐site disorder suppresses relaxation and eliminates QME signatures by inhibiting transport‐assisted mixing and enhancing the dominance of slow modes. Within the explored parameter regime, the Stark field induces significantly stronger retardation than disorder. We further show that symmetry‐projected entropy imbalance is particularly sensitive to charge‐sector decoherence in reduced subsystems and provides a stringent probe of QME in bosonic platforms. Our results elucidate the essential role of interactions in enabling anomalous relaxation in open lattice systems and connect the suppression of QME under spatial inhomogeneity to localization phenomena in tilted and disordered Bose–Hubbard chains.

Acute stress exposure can elicit analgesic responses in multiple pain models. Research indicates that dopaminergic pathways in the hippocampus contribute to the analgesic responses elicited by forced swim stress, considered a combination of physical and psychological stress. Since psychological and physical stresses can trigger different brain pathways and areas, this study has examined how dopaminergic receptors in the CA1 region of the hippocampus affect the pain relief induced by restraint stress (RS), generally considered a psychological stress, in an acute pain model. Ninety-six Wistar rats underwent stereotaxic surgery, during which a cannula was unilaterally implanted in the CA1 region of the hippocampus. Five minutes prior to exposure to RS, D1- and D2-like dopamine receptor antagonists (SCH23390 and sulpiride, respectively) or their respective carriers, saline and DMSO, were administered in different doses (0.25, 1, and 4 µg/0.5 µl per rat) into the CA1 area. The analgesic effects of RS were examined with and without dopaminergic receptor antagonists using the tail-flick test. This study's findings indicated that the administration of SCH23390 and sulpiride into the CA1 area of the hippocampus at the maximal doses (4 µg/0.5 µl; P < 0.001) markedly diminished the analgesic benefits of RS in the acute pain paradigm. The magnitude of estimated ED50s in the effect of these antagonists on reducing the RS-induced analgesia was 1.64 µg for SCH23390 and 2.79 µg for sulpiride, suggesting that both dopamine D1-like and D2-like receptors in the CA1 region of the hippocampus likely contribute to the analgesic effects of RS in the rats.

ABSTRACT For two given graphs and , a graph is said to be weakly ‐saturated if is a spanning subgraph of which has no copy of as a subgraph and one can add all edges in to in some order so that a new copy of is created at each step. The weak saturation number is the minimum number of edges of a weakly ‐saturated graph. In this paper, we deal with the relation between and , where denotes the Erdős–Rényi random graph and denotes the complete graph on vertices. For any graph and constant , we prove that with high probability. Also, for some graphs , including complete graphs, complete bipartite graphs, and connected graphs with minimum degree or , it is shown that there exists an such that, for every with high probability.