Phase-modulated single-photon nonreciprocal transport and directional router in a waveguide-cavity-emitter system beyond the chiral coupling

We propose a potentially practical scheme for the controllable single-photon transport via waveguides which are coupled to a microcavity-emitter system. The microcavity-emitter system consists of a V-type three-level emitter and two or one single-mode microcavity. A driving field is used to drive a hyperfine transition between two upper excited states of the V-type three-level emitter. Beyond chiral coupling between waveguides and microcavity-emitter system, we show that the perfectly nonreciprocal single-photon transport in a single waveguide and the single-photon router with 100% routing probability in two waveguides can be achieved. Interesting enough, whether the nonreciprocal single-photon transport or the single-photon router can be switched periodically by adjusting the phase associated with microcavity-emitter coupling strength and the driving field. The complete physical explanation of the underlying mechanism is presented.

Time and Causality: A Thermocontextual Perspective

The Thermocontextual Interpretation (TCI) is proposed here as an alternative to existing interpretations of physical states and time. Prevailing interpretations are based on assumptions rooted in classical mechanics. Logical implications include the determinism and reversibility of change, and an immediate conflict. Determinism underlies causality, but causality implies a distinction between cause and effect and an arrow of time, conflicting with reversibility. Prevailing interpretations also fail to explain the empirical irreversibility of wavefunction collapse without untestable and untenable metaphysical implications. They fail to reconcile nonlocality and relativity without invoking superdeterminism or unexplained superluminal correlations. The Thermocontextual Interpretation defines a system’s state with respect to its actual surroundings at a positive ambient temperature. The TCI bridges existing physical interpretations and thermodynamics as special cases, which define states either with respect to an absolute-zero reference or with respect to a thermally equilibrated reference. The TCI defines system time as a complex property of state spanning both reversible mechanical time and irreversible thermodynamic time, and it distinguishes between system time and the reference time of relativity and causality, as measured by an observer’s clock. And, the TCI provides a physical explanation for nonlocality, consistent with relativity, without hidden variables, superdeterminism, or “spooky action.”

Time and Causality: A Thermocontextual Perspective

The Thermocontextual Interpretation (TCI) is proposed here as an alternative to existing interpretations of physical states and time. Prevailing interpretations are based on assumptions rooted in classical mechanics. Logical implications include the determinism and reversibility of change, and an immediate conflict. Determinism underlies causality, but causality implies a distinction between cause and effect and an arrow of time, conflicting with reversibility. Prevailing interpretations also fail to explain the empirical irreversibility of wavefunction collapse without untestable and untenable metaphysical implications. They fail to reconcile nonlocality and relativity without invoking superdeterminism or unexplained superluminal correlations. The Thermocontextual Interpretation defines a system’s state with respect to its actual surroundings at a positive ambient temperature. The TCI bridges existing physical interpretations and thermodynamics as special cases, which define states either with respect to an absolute-zero reference or with respect to a thermally equilibrated reference. The TCI defines system time as a complex property of state spanning both reversible mechanical time and irreversible thermodynamic time, and it distinguishes between system time and the reference time of relativity and causality, as measured by an observer’s clock. And, the TCI provides a physical explanation for nonlocality, consistent with relativity, without hidden variables, superdeterminism, or “spooky action.”

Sublimation-driven morphogenesis of Zen stones on ice surfaces

In this article, the formation of Zen stones on frozen lakes and the shape of the resulting pedestal are elucidated. Zen stones are natural structures in which a stone, initially resting on an ice surface, ends up balanced atop a narrow ice pedestal. We provide a physical explanation for their formation, sometimes believed to be caused by the melting of the ice. Instead, we show that slow surface sublimation is indeed the physical mechanism responsible for the differential ablation. Far from the stone, the sublimation rate is governed by the diffuse sunlight, while in its vicinity, the shade it creates inhibits the sublimation process. We reproduced the phenomenon in laboratory-scale experiments conducted in a lyophilizer and studied the dynamics of the morphogenesis. In this apparatus, which imposes controlled constant sublimation rate, a variety of model stones consisting of metal disks was used, which allows us to rule out the possible influence of the thermal conduction in the morphogenesis process. Instead, we show that the stone only acts as an umbrella whose shade hinders the sublimation, hence protecting the ice underneath, which leads to the formation of the pedestal. Numerical simulations, in which the local ablation rate of the surface depends solely on the visible portion of the sky, allow us to study the influence of the shape of the stone on the formation of the ice foot. Finally, we show that the far-infrared black-body irradiance of the stone itself leads to the formation of a depression surrounding the pedestal.

Aerodynamic Loading Considerations of Three-Shaft Engine Compression System During Surge

Compressor surge imposes a limit on aero-engine operability and can compromise integrity because of significant aerodynamic loads imparted on the engine components. The aim of this paper is to use 3D unsteady CFD to predict the surge loadings on a modern three spool engine. The computations are performed using a whole-assembly approach. In this work, the effect of two types of surge initiation on the maximum loading recorded during surge are studied and a physical explanation of the main phenomena which contribute to those loadings is offered. The engine is matched at a high power condition and the surge inception is via throttling of the high pressure compressor (HPC) or turning of the intermediate pressure compressor (IPC) variable stator vanes. It was found that in an aero-engine surge event, the maximum overpressure are caused by a combined effect of the surge shock wave passing and high pressure gas blown towards the front of the engine during depressurisation. The overpressure is dictated by the compression system exit pressure at the moment of the surge inception. The surge initiation via HPC throttling produces larger overpressure and therefore, should be considered for design considerations.

Investigation of β-Ga2O3-based HEMT for Low Noise Amplification and RF Application

Here we demonstrate a two-dimensional β-gallium oxide-based high electron mobility transistor (HEMT) comprising of a finite gap—access region gap (L_ARG ) in Ohmic-contact access regions with record transconductance linearity. Apart from limiting two-dimensional electron gas (2DEG) density n_s dependency on gate voltage, higher saturation current is estimated for the proposed design. Since the access regions length directly affects the Capacitance of the device and resultant switching applications. In this work, the effect of the gate-source and gate-drain length on device linearity is performed using Atlas-2D simulations. C-V characteristics of the proposed device are explained based on the physical explanation and validated using appropriate models. The higher values of transconductance g_m and current gain cut-off frequency f_T on a large span of operating voltages ensure improved transistor performance for low-noise amplification and RF application and are reported for the first time.<br>

Investigation of β-Ga2O3-based HEMT for Low Noise Amplification and RF Application

Here we demonstrate a two-dimensional β-gallium oxide-based high electron mobility transistor (HEMT) comprising of a finite gap—access region gap (L_ARG ) in Ohmic-contact access regions with record transconductance linearity. Apart from limiting two-dimensional electron gas (2DEG) density n_s dependency on gate voltage, higher saturation current is estimated for the proposed design. Since the access regions length directly affects the Capacitance of the device and resultant switching applications. In this work, the effect of the gate-source and gate-drain length on device linearity is performed using Atlas-2D simulations. C-V characteristics of the proposed device are explained based on the physical explanation and validated using appropriate models. The higher values of transconductance g_m and current gain cut-off frequency f_T on a large span of operating voltages ensure improved transistor performance for low-noise amplification and RF application and are reported for the first time.<br>

Novel solitary and resonant multi-soliton solutions to the (3 + 1)-dimensional potential-YTSF equation

In this study, the (3 + 1)-dimensional potential-Yu–Toda–Sasa–Fukuyama equation arising from the (3 + 1)-dimensional Kadomtsev–Petviashvili equation is investigated in detail by using two powerful approaches. First, the generalized resonant multi-soliton solution is generated via the simplified linear superposition principle. Second, after applying the simplest equation method, the generalized single solitary solution is extracted. The results show that the obtained solutions are perfect. The physical explanation of the obtained solutions is depicted in various 3D and 2D figures, which are used to illustrate that the interactions of resonant multi-soliton waves are inelastic. Ultimately, the study reveals that the inelastic interactions can be determined by the sign of the wave related number [Formula: see text].

Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

We studied the spectral dependence of the Vickers microhardness HV0.025 of CdZnTe and CdZnTeSe samples upon illumination and found out that it increases over the entire applied spectral range of 1540–750 nm. We also found out that the photoconductivity and microhardness are correlated. We observed changes in the correlation diagram (change of slope and an abrupt change of HV0.025 at several wavelengths of the illuminating light). Based on measurements of the relative changes of the space charge upon illumination using the Pockels effect, we suggest that the observed spectral dependence of positive photoplastic effect in CdZnTe and CdZnTeSe can be explained by the trapping of photoinduced electrons and holes, which affects the motion of the partial dislocations. The underlying physical explanation relies on the assumption that reconstructed bonds break before dislocation glide.