Ensuring optimum thermal regimes of operation of engines, electronics, accumulator batteries, and other electric transport equipment is a problem of current importance. Granted the diversity of cooling systems of heat-releasing objects, the use of heat pipes and thermosyphons is one optimum area. Heat pipes and thermosyphons are noiseless in operation and do not require energy expenditures, which is very important for cordless electric transport. They can receive heat from the object being cooled, remove it beyond the boundaries of the volume filled with equipment and then transfer it to the cooling liquid or air. Using heat exchangers on heat pipes, it is possible not only to optimize heat regimes of the operation of an electric engine, batteries, power electronic equipment, but also to ensure the work of onboard climate control systems.

The long-term relaxation dynamics of neutral excitations with spin 1 in the Laughlin liquid at an electron filling factor of 1/3 has been studied. It has been found that there are two types of excitations with the same energies, the relaxation times of which to the ground state differ by at least two orders of magnitude. Assumptions are made about the nature of these excitations.

In this paper, the authors present the design, operating principle, and results from the study of two-phase heat conductors intended for thermal regulation of heat-loaded equipment: ring thermosyphons with a horizontally located evaporator and condenser and a porous coating in the evaporator. Two modifications of thermosyphons—with a cylindrical evaporator and liquid cooling of the condenser and with a flat evaporator and air cooling of the condenser—were tested. The porous wick promotes uniform distribution of liquid and heat flow in the longitudinal and cross sections of the evaporator and equalization of the temperature field over the surface of the evaporator and, consequently, the cooled object. Thermosyphons are made of copper, and the operating fluids are water and freon R245fa.

An ensemble of neutral excitations is constructed experimentally in the Laughlin liquid at the electron filling factor 1/3. The excitations are found to induce a nonlinear optical response, manifested as a quadratic dependence of the reflection signal on the excitation power. The reported experimental results indicate that the observed effect is due to the anti-Stokes–Stokes scattering of light from the excited Laughlin liquid.

An ensemble of neutral excitations in a 1/3 Laughlin liquid is studied experimentally. It has been found that excitations induce a nonlinear optical response in the form of a quadratic dependence of the reflection signal on the pump power. The reported experimental results have shown that the observed effect is due to the contribution of the coherent anti-Stokes–Stokes scattering from the excited Laughlin liquid.

Экспериментально исследован ансамбль нейтральных возбуждений в лафлиновской жидкости в дробном состоянии 1/3. Обнаружено, что возбуждения вызывают нелинейный оптический отклик, проявляющийся в виде квадратичной зависимости сигнала отражения от мощности возбуждения. Приведенные экспериментальные результаты показывают, что наблюдаемый эффект обусловлен вкладом когерентного антистоксово-стоксова рассеяния света от возбужденной лафлиновской жидкости.

A new experimental technique is proposed for studying bulk states under conditions of the fractional quantum Hall effect.

Neutral excitations in a two-dimensional electron system with an orbital and spin quantum number of 1 in the vicinity of filling factor v = 3/2 are studied experimentally. It is found that the rate of excitation relaxation to the ground state slows very strongly at v = 3/2, even though the number of vacancies in the ground state suitable for the relaxation of excitations is macroscopically large. It is shown that neutral excitations with orbital and spin quantum numbers of 1 in the state of v = 3/2 are an example of topologically protected excitation with different spin orderings in the ground and excited states. The state of v = 3/2 is an example of a locally incompressible fractional state of the quantum Hall effect, which is neither a Laughlin liquid nor an integer state of composite fermions.

The temperature dependence of the resonant light reflection spectra from the Laughlin liquid in the 1/3 fractional quantum Hall state is measured. It is shown that the resonant reflection lines under conditions corresponding to the formation of the fractional quantum Hall state have a cooperative nature, and their energies do not obey the requirements of the “hidden symmetry.” The energies of spin excitations in the Laughlin liquid are measured using the resonant reflection spectra, and the results of the experiment are compared to the results obtained by solving the Schrödinger equation for several particles.

It is found that the thermalization of triplet spin-flip magneto-excitons in a quantum Hall dielectric is an unprecedentedly long process for translation-invariant nonequilibrium electronic systems. It is shown that a magneto-fermionic condensate, a state characterized by the ability to rapidly transfer spin over macroscopic distances, is formed by spin-flip excitons with generalized momenta on the order of the reciprocal magnetic length.

Two-dimensional electron systems in a quantizing magnetic field are regarded as of exceptional interest, considering the possible role of anyons—quasiparticles with non-boson and non-fermion statistics—in applied physics. To this day, essentially none but the fractional states of the quantum Hall effect (FQHE) have been experimentally realized as a system with anyonic statistics. In determining the thermodynamic properties of anyon matter, it is crucial to gain insight into the physics of its neutral excitations. We form a macroscopic quasi-equilibrium ensemble of neutral excitations - spin one anyon complexes in the Laughlin state ν = 1/3, experimentally, where ν is the electron filling factor. The ensemble is found to have such a long lifetime that it can be considered the new state of anyon matter. The properties of this state are investigated by optical techniques to reveal its Bose properties.

The spin coherence of two-dimensional electrons is determined by two independent mechanisms: a single particle relaxation owing to spatially fluctuating magnetic field, and a many-particle exchange interaction maintaining collective precession of the electron spins with a common Larmor frequency. In this study, we investigate the structure of a time-resolved Kerr rotation signal for the different spin states of two-dimensional electron system subjected to the quantizing magnetic field. At low temperatures, when spin–spin correlations define the ground state of the two-dimensional electron system, our data show a nonlinear damping of Larmor oscillations. The amplitude and the correlation length of the fluctuating magnetic field acting on individual electron spins are estimated.

We studied neutral excitations in a two-dimensional electron system with an orbital momentum $\Delta M = 1$ and spin projection over magnetic field axis $\Delta S_z = 1$ in the vicinity of a filling factor of 3/2. It is shown that the 3/2 state is a singular point in the filling factor dependence of the spin ordering of the two-dimensional electron system. In the vicinity of $\nu=3/2$, a significant increase in the relaxation time ($\tau = 13$ $\mu\text{s}$) for the excitations to the ground state is exhibited even though the number of vacancies in the lowest energy level is macroscopically large. The decrease of the relaxation rate is related to the spin texture transformation in the ground state induced by spin flips and electron density rearrangement. We claim the 3/2 state is a locally incompressible fractional quantum Hall state.

Resonant and nonresonant photoluminescence spectra of a two-dimensional electron system have been studied under the conditions of the formation of the 1/3 fractional quantum Hall effect state. It has been shown that resonant photoluminescence, in contrast to nonresonant photoluminescence, is a universal marker of the formation of the 1/3 state in the bulk of the two-dimensional system. It has been found that the probabilities of optical transitions from the zeroth Landau level of electrons in the 1/3 state vary so strongly that these variations cannot be explained within the existence theoretical concepts.

Magneto-fermionic condensate under study is a Bose-Einstein condensate of cyclotron spin-flip magnetoexcitons in a quantum Hall insulator. This condensate features unique properties such as millisecond range lifetime and hundreds of micrometers of propagation length. In this study, utilizing the photo-induced resonant reflection technique, we measured the exciton escape time. Finally, we estimated the exciton condensate propagation velocity as 25 m/s, which is much higher than a single particle propagation velocity. We also proposed a mechanism of exciton condensation.

In a dilute gas of triplet magnetoexcitons, complete thermalization does not occur because the energy and momentum cannot be conserved simultaneously. Relaxation to the lowest energy state becomes possible owing to exciton—exciton scattering upon reaching a certain critical exciton density. Since thermalization times are extremely large, ensembles of magnetoexcitons are substantially nonequilibrium and consist of above-condensate magnetoexcitons with generalized momenta close to zero and magnetoexcitons at the energy minimum with momenta about the inverse magnetic length. It has been shown experimentally that the magnetoexciton density is transferred to long distances not by all magnetoexcitons, but by those whose momentum is close to the inverse magnetic length, ∼10 6 cm −1 , and these magnetoexcitons form a magnetofermionic condensate.