Cryogenic field-effect transistors (FETs) offer great potential for a wide range of applications, the most notable example being classical control electronics for quantum information processors. In the latter context, on-chip FETs with low power consumption are a crucial requirement. This, in turn, requires operating voltages in the millivolt range, which are only achievable in devices with ultra-steep subthreshold slopes. However, in conventional cryogenic metal-oxide-semiconductor (MOS)FETs based on bulk material, the experimentally achieved inverse subthreshold slopes saturate around a few mV/dec due to disorder and charged defects at the MOS interface. FETs based on two-dimensional materials offer a promising alternative. Here, we show that FETs based on Bernal stacked bilayer graphene encapsulated in hexagonal boron nitride and graphite gates exhibit inverse subthreshold slopes of down to 250 ${\mu}$V/dec at 0.1 K, approaching the Boltzmann limit. This result indicates an effective suppression of band tailing in van-der-Waals heterostructures without bulk interfaces, leading to superior device performance at cryogenic temperature.

The coupled transport of charge and orbital angular momentum (OAM) lies at the core of orbitronics. Here, we examine the reciprocal relation in orbital-charge-coupled transport in thin films, treating bulk and surface contributions on equal footing. We argue that the conventional definition of orbital current is ill-defiled, as it violates reciprocity due to the nonconservation of OAM. This issue is resolved by adopting the so-called \emph{proper} orbital current, which is directly linked to orbital accumulation. We establish the reciprocal relation for the \emph{global} (spatially integrated) response between orbital and charge currents, while showing that their \emph{local} (spatially resolved) responses can differ significantly. In particular, we find large surface contributions that may lead to nonreciprocity when currents are measured locally. These findings are supported by first-principles calculations on W(110) and Pt(111) thin films. In W(110), orbital-charge interconversion is strongly nonreciprocal at the layer level, despite exact reciprocity in the integrated response. Interestingly, spin-charge interconversion in W(110) remains nearly reciprocal even locally. In contrast, Pt(111) exhibits local nonreciprocity for both orbital-charge and spin-charge conversions, which we attribute to strong spin-orbit coupling. We propose that such local distinctions can be exploited to experimentally differentiate spin and orbital currents.

The tumbling dynamics of individual polymers in semidilute solution is studied by large-scale non-equilibrium mesoscale hydrodynamic simulations. We find that the tumbling time is equal to the non-equilibrium relaxation time of the polymer end-to-end distance along the flow direction and strongly depends on concentration. In addition, the normalized tumbling frequency as well as the widths of the alignment distribution functions for a given concentration-dependent Weissenberg number exhibit a weak concentration dependence in the cross-over regime from a dilute to a semidilute solution. For semidilute solutions a universal behavior is obtained. This is a consequence of screening of hydrodynamic interactions at polymer concentrations exceeding the overlap concentration.

The mini proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024) [this https URL]" held at J-PARC, February 19-21, 2024, are presented. The workshop was devoted to discussing the physics case that connects both the present and the future Hadron Experimental Facility at J-PARC, covering a wide range of topics in flavor, hadron, and nuclear physics related to both experimental and theoretical activities being conducted at the facility.

The dynamical Casimir effect is the physical phenomenon where the mechanical energy of a movable wall of a cavity confining a quantum field can be converted into quanta of the field itself. This effect has been recognized as one of the most astonishing predictions of quantum field theory. At the quantum scale, the energy conversion can also occur incoherently, namely without an physical motion of the wall. We employ quantum thermodynamics to show that this phenomenon can be employed as a tool to cool down the wall when there is a non-vanishing temperature gradient between the wall and the cavity. At the same time, the process of heat-transfer enables to share the coherence from one cavity mode, driven by a laser, to the wall, thereby forcing its coherent oscillation. Finally, we show how to employ one laser drive to cool the entire system including the case when it is composed of other subsystems.

Agent-based models (ABMs) have emerged as distinguished tools for epidemic modeling due to their ability to capture detailed human contact patterns. ABMs can support decision-makers in times of outbreaks and epidemics substantially. However, as a result of missing correspondingly resolved data transmission events are often modeled based on simplified assumptions. In this article, we present a framework to assess the impact of these simplifications on epidemic prediction outcomes, considering superspreading and workplace transmission events. We couple the VADERE microsimulation model with the large-scale MEmilio-ABM and compare the outcomes of four outbreak events after 10 days of simulation in a synthetic city district generated from German census data. In a restaurant superspreading event, where up to four households share tables, we observe 17.2~\% more infections on day 10 after the outbreak. The difference increases to 46.0 % more infections when using the simplified initialization in a setting where only two households share tables. We observe similar outcomes (41.3 % vs. 9.3 % more infections) for two workplace settings with different mixing patterns between teams at work. In addition to the aggregated difference, we show differences in spatial dynamics and transmission trees obtained with complete or reduced outbreak information. We observe differences between simplified and fully detailed initializations that become more pronounced when the subnetworks in the outbreak setting are mixing less. In consequence and aside from classical calibration of models, the significant outcome differences should drive us to develop a more profound understanding of how and where simplified assumptions about transmission events are adequate.