桜美林大学

In this note, we reexamine decoherence effects in quantum field theories with gravity duals. The thought experiment proposed in [1, 2], which reveals novel decoherence patterns associated with black holes, also manifests itself from the perspective of the boundary theory. In particular, we consider a moving mirror coupled to quantum critical theories characterized by a dynamical exponent z that are dual to asymptotically Lifshitz geometries. The interference experiment occurs on the boundary, where a superposition of two spatially separated quantum states of a mirror is maintained for a finite time tau 0 before recombination. We find that the interaction with a quantum field at finite temperature, arising from the presence of a Lifshitz black hole, leads to a constant decoherence rate. In contrast, for the zero-temperature case corresponding to pure Lifshitz spacetime, the decoherence rate vanishes in the large-time limit tau 0 -> infinity. Remarkably, in the zero-temperature regime, the decoherence exhibits a power-law decay at large tau 0 as z -> infinity, a behavior reminiscent of the decoherence patterns seen in extremal black hole geometries. In addition, we investigate the decoherence of one particle in an EPR pair constructed holographically. Our results indicate that causality plays a crucial role in determining whether the entanglement leads to the suppression of decoherence in the other particle.

In low-energy supergravity treatment of type IIB superstring on general D-instanton wormhole profiles in the bulk, we obtain non-vanishing scalar two-point functions in addition to the vanishing ⟨ τ^* τ^* ⟩ that corresponds to the BPS amplitude detected by two D-instantons at their respective boundaries. This is exploited to show that the modes of broken local supersymmetry in the bulk deliver the fermionic (diagonal) modes on the boundaries through the deformation by the form of current-current two point functions propagating on the tree level cylinder geometry. Our treatment is generalizable to multi D-instanton cases and general Euclidean branes.

BACKGROUND:Health status in old age can be influenced by financial disadvantages both at present and in earlier life stages; however, few studies have focused on the long-term individual patterns of financial disadvantage over the life course. This study examined the relationship between trajectories of financial disadvantage over the life course and depressive mood among community-dwelling older Japanese adults. METHODS:Data were obtained from the 2012 National Survey of the Japanese Elderly using a two-stage stratified random sampling method. The sample consisted of 1,324 adults aged ≥60 years. We retrospectively assessed financial disadvantage at four life-course benchmark periods: ≤18 years old, 25-35 years old, 35-50 years old, and current age. Depressive mood was measured using the 8-item Center for Epidemiologic Studies Depression Scale. RESULTS:We identified five distinct life-course financial disadvantage trajectories using group-based mixture modeling: "persistently affluent" (22.1%), "increasing affluence" (21.7%), "consistently modest" (28.0%), "decreasing affluence" (11.3%), and "persistently poor" (17.0%). A logistic regression analysis showed that people in the "increasing affluence" subgroup were less likely to have a depressive mood than those in the "persistently poor" subgroup, after adjusting for potential covariates, including current income and parental educational attainment. This association was more prominent in women than in men. CONCLUSION:The experience of escaping from financial disadvantages may bolster the mental health of older adults, regardless of sociodemographic characteristics, health behaviors, and health conditions. The mental health benefits of increasing affluence throughout the life course may be even stronger than the benefits of experiencing persistent affluence.

We study how rotation modifies the constraints on MeV-scale axion-like particles (ALPs) coupled to photons derived from SN 1987A. We constrain the ALP parameter space based on both the energy-loss argument and the gamma-ray limits, and examine how these constraints are affected by stellar rotation. Adopting initial angular velocities of Ω_0 = 0.0 and 1.0 rad s^-1 in the iron core, we carry out two-dimensional core-collapse supernova simulations for three progenitor models - a 14 + 9M_⊙ binary and 13M_⊙ and 18M_⊙ single stars with solar metallicity - and estimate ALP emission rates through post-processing. We find that rotation suppresses ALP emission by reducing the core temperature via centrifugal support. Rotation also reduces the neutrino luminosity, but the suppression of ALP emission is more effective, leading to relaxed constraints within a simplified criterion based on the energy-loss argument. This relaxation is particularly pronounced in the rotating 18M_⊙ model, where a substantial decrease in the central temperature occurs at t_pb = 0.8 - 1 s. In this simplified criterion, such rapid temporal variations in temperature indicate that the resulting constraints depend sensitively on both the evaluation time and the underlying supernova model. For a gamma-ray limit from the SN 1987A observation, rotation has a negligible impact on the constraint. This is because the ALP-induced gamma-ray fluence observed at Earth is proportional to the fourth power of the ALP-photon coupling constant, making the constraint relatively insensitive to the rotational suppression of ALP emission.