arXiv subjects
Publications and source records attributed to Dima Cheskis.
We apply the formalism of coherent states in quantum optics to pomeron evolution and show that evolving squeezed pomeron states are equivalent to pomeron fan diagrams at the leading order of perturbative expansion. Based on our results, we interpret the action of the displacement operator as pomeron propagation and the action of the squeeze operator as pomeron interaction.
Non-contact temperature sensors are widely used, often utilizing infrared light for temperature measurement. However, specific applications demand non-contact detection, particularly within closed containers containing fluids or gases, where optical methods are unsuitable. Our approach is designed precisely for this purpose. We conducted measurements, introduced a prototype of our detector, and confirmed its compatibility with nonmagnetic containers.
We present a comprehensive study on the spatio temporal weak measurement of a chiral ultrafast optical pulse. We create a chiral vector wave packet by transmitting ultrashort laser pulse via a birefringent or magneto-optic medium. Employing time-resolved leakage radiation microscopy, we examine how the real and imaginary components of the weak value parameter ($\epsilon$) influence pulse propagation over time. Our technique allows us to detect and categorize the temporal polarization fluctuation in a $75$ fs pulse with an excellent repeatability. The achieved experimental results demonstrate a satisfactory consistency with the theoretical predictions.
This paper shows that in Laser-Induced Plasma Lasers (LIPL), the collisionally assisted transitions that lead to the inversion population on an upper-generation level E up may be partly forbidden. The spin-orbit coupling may increase the oscillator strength of such transitions. It also demonstrates that collisions between electrons and excited atoms can strongly increase the atoms' energy, creating a population inversion at the E up level, which may lie about 1 eV above the pumped level E pump . Examples of oscillator strengths and collisional transition rate estimates are provided using linear-response time-dependent density functional theory (TDDFT) in the Casida formalism.
We develop an effective thermodynamic model for a black-hole interior composed of scalar quasiparticles. The interior is represented by two regions: a dense core and a surrounding crust, whose properties are controlled by the quasiparticle kinetics. In the core, quasiparticles are assumed to have vanishing classical kinetic energy, so the total core energy is dominated by a potential-energy functional $U(N)$ that depends only on the quasiparticle number $N$. As a consequence, the appropriate intensive variable governing the core thermodynamics is an inverse-temperature--like parameter $\beta$, introduced as the thermodynamic conjugate to $U$; it replaces the usual kinetic temperature $T$ in the core equations of state and can drive the core pressure and energy density negative in the relevant regime. Different core states are further characterized by the mean occupation number $\eta$. In the crust, quasiparticles remain trapped at finite kinetic temperature, and the no-escape condition is implemented via a truncation of the phase-space integrals, yielding an explicit analytic coupling between thermodynamics and gravity. The resulting framework provides a unified quasiparticle description of core and crust, clarifies the thermodynamic origin of negative pressure/energy in the interior, and provides an effective thermodynamic setting for exploring how semiclassical or microscopic resolutions of the singularity problem might be constrained.
Decoupling the global Berry-curvature contribution to the anomalous Hall conductivity (AHC) from local domain- and texture-related contributions in bulk ferromagnetic Weyl semimetals is difficult in standard measurements. We address this in a $\sim$670$\mu$m-thick Co$_3$Sn$_2$S$_2$ single crystal using a contact architecture that promotes depth-distributed current flow. We find that the AHC depends on the field-enforced domain state: above $\sim$0.3\,T, a single- or few-domain configuration reveals a momentum-space intrinsic Berry-curvature response, with a crossover near $\sim$125\,K driven by rapid magnetization decrease and reduced magnetic anisotropy. In low-field zero-field-cooled (ZFC) multidomain states, the Hall response is modified by domain physics, with possible real-space Berry curvature and moderate extrinsic contributions. These results demonstrate contact engineering as a practical, non-invasive strategy for separating the momentum-space intrinsic AHC from domain-mediated and extrinsic contributions in thick Weyl semimetal crystals.
Many modern electronic devices utilize linear Hall sensors to measure current and the magnetic field, as well as to perform switching and latching operations. Smartphones, laptops, and e-readers all work with very low (sub-mA) currents. To perform a switching function in such low-power devices, however, a Hall sensor must be able to work in the μA regime. This paper demonstrates, for the first time, the ability of a standard Hall detector to work in the μA regime between 0 and 0.7 Tesla. A second important application of this technology is the measurement of electron transport parameters in thin films, which is essential to elucidating their electronic behavior. The development of new devices using thin films demands very precise measurements of tiny electrical currents, low-intensity magnetic fields, and other small signals. The proposed system delivers a very small but stable electric current without external noise, and can be used to measure small transport parameters with very high precision. We demonstrate the capabilities of this system by measuring the slope of the Hall effect with a four-point probe at current intensities of 100, 10, and 1 μA.