This condition, akin to the Breitenlohner-Freedman bound, serves as a necessary requirement for the stability of asymptotically anti-de Sitter (AAdS) spacetimes.
Quantum paraelectrics' light-induced ferroelectricity opens a new path toward dynamic stabilization of hidden orders within quantum materials. This letter investigates the potential for inducing a transient ferroelectric phase in quantum paraelectric KTaO3 through intense terahertz excitation of the soft mode. The terahertz-driven second-harmonic generation (SHG) signal displays a prolonged relaxation, extending to 20 picoseconds at a temperature of 10 Kelvin, a characteristic that might be explained by the induction of ferroelectricity by light. We find that terahertz-induced coherent soft-mode oscillations, whose hardening correlates with fluence, conforming to a single-well potential model, show that, even under 500 kV/cm of terahertz pulse intensity, no global ferroelectric phase transition occurs in KTaO3. Instead, the prolonged decay of the sum frequency generation signal is ascribed to a moderate, terahertz-driven, dipolar correlation involving defect-induced local polar structures. We consider the effects our findings have on current investigations of the terahertz-induced ferroelectric phase within quantum paraelectrics.
We delve into the influence of fluid dynamics, including pressure gradients and wall shear stress within a channel, on the deposition of particles in a microfluidic network, leveraging a theoretical model. The transport of colloidal particles in pressure-driven packed bed systems has been observed; under low pressure gradients, deposition occurs locally at the inlet, while under higher gradients, deposition occurs uniformly along the flow. To capture the observed qualitative characteristics in experiments, a mathematical model and agent-based simulations are developed. Our exploration of the deposition profile within a two-dimensional phase diagram, determined by pressure and shear stress thresholds, unveils two distinct phases. We offer an explanation of this apparent phase transition by drawing a comparison to fundamental one-dimensional models of mass accumulation, where the phase transition is established analytically.
The excited states of ^74Zn (N=44) were investigated using gamma-ray spectroscopy as a consequence of the decay of ^74Cu. Curcumin analog C1 concentration Angular correlation analysis definitively established the 2 2+, 3 1+, 0 2+, and 2 3+ states within the ^74Zn nucleus. Measurements of the -ray branching ratios and E2/M1 mixing ratios for transitions de-exciting the 2 2^+, 3 1^+, and 2 3^+ states enabled the determination of relative B(E2) values. Among other observations, the 2 3^+0 2^+ and 2 3^+4 1^+ transitions were observed for the very first time. New large-scale microscopic shell-model calculations yield excellent agreement with the presented results, which are discussed in terms of the underlying structures and the contribution of neutron excitations spanning the N=40 gap. The ground state of ^74Zn is predicted to be characterized by an augmented axial shape asymmetry, which is referred to as triaxiality. Consequently, the identification is made of a K=0 band characterized by exceptional softness in its shape, especially in its excited state. The island of inversion, associated with N=40, appears to extend its coastal regions beyond the previously established Z=26 mark, as per nuclide charts.
Repeated measurements interspersed with many-body unitary dynamics exhibit a rich array of phenomena, including measurement-induced phase transitions. Feedback-control operations, which guide the dynamics toward an absorbing state, are employed to examine the entanglement entropy's behavior at the absorbing state phase transition. In short-range control procedures, we witness a phase transition characterized by distinctive subextensive scaling patterns in entanglement entropy. The system's operation is characterized by a transition between volume-law and area-law phases for prolonged-range feedback mechanisms. Entanglement entropy fluctuations and absorbing state order parameter fluctuations are completely intertwined by sufficiently strong entangling feedback operations. Consequently, the universal dynamics of the absorbing state transition are inherited by entanglement entropy in this instance. It is important to note that arbitrary control operations are not governed by the same principles as the two, distinct transitions. Our findings are quantitatively supported by a framework incorporating stabilizer circuits and classical flag labels. The problem of observing measurement-induced phase transitions receives a new perspective through our results.
Discrete time crystals (DTCs), a topic of growing recent interest, are such that the properties and behaviours of most DTC models remain hidden until after averaging over the disorder. This letter introduces a straightforward, disorder-free, periodically driven model that showcases non-trivial dynamical topological order, stabilized by Stark many-body localization. We confirm the existence of the DTC phase through analytical analysis based on perturbation theory, coupled with compelling numerical evidence from observable dynamics. The new DTC model presents a promising avenue for future experiments, deepening our comprehension of DTCs. Immune enhancement With its inherent dispensability of specialized quantum state preparation and the strong disorder average, the DTC order can be executed on noisy intermediate-scale quantum hardware with a substantial reduction in required resources and repetitions. Moreover, the robust subharmonic response is accompanied by novel robust beating oscillations, a characteristic feature of the Stark-MBL DTC phase, not observed in random or quasiperiodic MBL DTCs.
The puzzle of antiferromagnetic order, quantum criticality, and the manifestation of superconductivity at extremely low temperatures (in the millikelvin range) in the heavy fermion metal YbRh2Si2 continues to intrigue the scientific community. Measurements of heat capacity across a broad temperature spectrum, from 180 Kelvin to 80 millikelvin, are presented, utilizing current sensing noise thermometry. In zero magnetic field conditions, a noticeably sharp heat capacity anomaly emerges at 15 mK, which we associate with an electronuclear transition to a state possessing spatially modulated electronic magnetic order, reaching a peak amplitude of 0.1 B. Large moment antiferromagnetism and the potential for superconductivity are demonstrated in these outcomes.
Employing sub-100 femtosecond time resolution, we probe the ultrafast dynamics of the anomalous Hall effect (AHE) in the topological antiferromagnet Mn3Sn. Optical pulse excitations substantially elevate the electron temperature to a maximum of 700 Kelvin, and terahertz probe pulses unambiguously show the ultrafast suppression of the anomalous Hall effect preceding demagnetization. Microscopic calculations of the intrinsic Berry-curvature mechanism accurately reproduce the result, explicitly excluding any extrinsic contribution. Light-induced drastic control over electron temperature forms the cornerstone of our work, unveiling new avenues for deciphering the microscopic origin of nonequilibrium anomalous Hall effect (AHE).
Initially, we examine a deterministic gas of N solitons within the framework of the focusing nonlinear Schrödinger (FNLS) equation, scrutinizing the limit as N approaches infinity, with a point spectrum meticulously selected to interpolate a pre-defined spectral soliton density across a constrained region of the complex spectral plane. genetic algorithm Applying the deterministic soliton gas model to a disk-shaped domain and an analytically-defined soliton density, we observe the unexpected emergence of a one-soliton solution, whose spectrum's point lies at the center of the disk. Soliton shielding, we call it, describes this effect. Soliton shielding, a robust characteristic, persists in a stochastic soliton gas even when the N-soliton spectrum is randomly chosen; whether uniformly on a circle or from the statistics of Ginibre random matrix eigenvalues, the effect remains. This persistence is observed as N approaches infinity. An asymptotically step-like oscillatory physical solution is observed, whereby the initial profile takes the form of a periodic elliptic function within the negative x-region, and it declines exponentially rapidly in the positive x-axis.
Center-of-mass energies from 4189 to 4951 GeV are utilized to first measure the Born cross sections for the process e^+e^-D^*0D^*-^+. Data samples, collected by the BESIII detector at the BEPCII storage ring, represent an integrated luminosity of 179 fb⁻¹. Four hundred twenty, four hundred forty-seven, and four hundred sixty-seven GeV reveal three enhancements. The resonances' widths, specifically 81617890 MeV, 246336794 MeV, and 218372993 MeV, and masses, specifically 420964759 MeV/c^2, 4469126236 MeV/c^2, and 4675329535 MeV/c^2, respectively, exhibit statistical uncertainty first and systematic uncertainty second. The first resonance displays consistency with the (4230) state, the third resonance aligns with the (4660) state, and the observed (4500) state in the e^+e^-K^+K^-J/ process is compatible with the second resonance. For the first time, the e^+e^-D^*0D^*-^+ process has revealed the presence of these three charmonium-like states.
This proposed thermal dark matter candidate's abundance is established through the freeze-out of inverse decay processes. Parametrically, the relic abundance is a function solely of the decay width; nonetheless, the observed value requires that the coupling defining the width, along with the width itself, be exceedingly small, approaching exponential suppression. Consequently, the interaction between dark matter and the standard model is exceptionally weak, rendering it elusive to traditional detection methods. In upcoming planned experiments, researchers can potentially discover this inverse decay dark matter by searching for the long-lived particle that decays into it.
Quantum sensing techniques achieve exceptional sensitivity in detecting physical quantities, exceeding the limitations of the shot-noise limit. The technique, while promising in theory, has, in reality, faced obstacles, including phase ambiguity and low sensitivity, particularly when applied to small-scale probe states.