JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024601192
S. V. Aksenov
{"title":"Features of the Response of Majorana Quasiparticles in Superconducting Wires (Brief Review)","authors":"S. V. Aksenov","doi":"10.1134/S0021364024601192","DOIUrl":"10.1134/S0021364024601192","url":null,"abstract":"<p>Interest in hybrid quasi-one-dimensional systems with an inner semiconducting part coated with a superconductor (the so-called core/shell structure) has been grown in the last decade. Materials with a strong spin‒orbit coupling and a large <i>g</i>-factor (InAs, InSb) are chosen as semiconductors. Due to the proximity effect, such objects can be considered as superconducting wires, where the existence of Majorana states has been predicted. This review briefly summarizes the current experimental studies aimed at the detection of Majorana quasiparticle excitations in superconducting wires. Furthermore, prospects of using the interference geometry of devices including such wires are discussed. In particular, the coherent transport in a spatially inhomogeneous one-dimensional normal metal/superconductor/normal metal system, where normal metal wires serve as arms of an interference device, which interact with a normal metal contact, has been analyzed theoretically. It has been found that responses of Majorana and Andreev low-energy excitations of the device can be distinguished.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 1","pages":"56 - 65"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024601982
D. A. Safronenkov, G. Kh. Kitaeva
{"title":"Measurement of Correlations in the Parametric Down Conversion Field Using Analog Detectors","authors":"D. A. Safronenkov, G. Kh. Kitaeva","doi":"10.1134/S0021364024601982","DOIUrl":"10.1134/S0021364024601982","url":null,"abstract":"<p>A method to measure the correlation function of a biphoton field, which does not require single-photon detectors and photocount coincidence schemes, has been proposed and experimentally approved. It is based on the statistical analysis of current data from analog detectors. On an example of the operation of a scheme with analog photomultiplier tubes in the signal and idler channels of degenerate parametric down conversion, it has been shown that this new approach allows one to obtain correlation function values coinciding with the results of the standard photon counting technique. It has been shown how the absolute values of photon numbers and radiation power in the signal channel of the down conversion scheme are determined from the measured correlation function. Analog detection can expand the spectral and dynamic ranges of electromagnetic radiation for the application of quantum optic technologies. A method for the reference-free measurement of the spectral sensitivity of an analog photosensor module has been demonstrated as the first example of application.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 1","pages":"14 - 19"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024602926
N. N. Orlova, A. A. Avakyants, A. V. Timonina, N. N. Kolesnikov, E. V. Deviatov
{"title":"Crossover from Relativistic to Non-Relativistic Net Magnetization for MnTe Altermagnet Candidate","authors":"N. N. Orlova, A. A. Avakyants, A. V. Timonina, N. N. Kolesnikov, E. V. Deviatov","doi":"10.1134/S0021364024602926","DOIUrl":"10.1134/S0021364024602926","url":null,"abstract":"<p>We experimentally study magnetization reversal curves for MnTe single crystals, which is the altermagnetic candidate. Above 85 K temperature, we confirm the antiferromagnetic behavior of magnetization <i>M</i>, which is known for α-MnTe. Below 85 K, we observe anomalous low-field magnetization behavior, which is accompanied by the sophisticated <span>(M(alpha ))</span> angle dependence with beating pattern as the interplay between <span>(M(alpha ))</span> maxima and minima: in low fields, <span>(M(alpha ))</span> shows ferromagnetic-like 180° periodicity, while at high magnetic fields, the periodicity is changed to the 90° one. This angle dependence is the most striking result of our experiment, while it can not be expected for standard magnetic systems. In contrast, in altermagnets, symmetry allows ferromagnetic behavior only due to the spin–orbit coupling. Thus, we claim that our experiment shows the effect of weak spin–orbit coupling in MnTe, with crossover from relativistic to non-relativistic net magnetization, and, therefore, we experimentally confirm altermagnetism in MnTe.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 5","pages":"360 - 366"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0021364024602926.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024601489
I. V. Savitsky, P. B. Glek, R. M. Aliev, E. A. Stepanov, A. A. Voronin, A. A. Lanin, A. B. Fedotov
{"title":"Phase-Sensitive Plasma Nonlinearity Controlled by Ultrashort Pulses","authors":"I. V. Savitsky, P. B. Glek, R. M. Aliev, E. A. Stepanov, A. A. Voronin, A. A. Lanin, A. B. Fedotov","doi":"10.1134/S0021364024601489","DOIUrl":"10.1134/S0021364024601489","url":null,"abstract":"<p>The generation of spectral components sensitive to the carrier-envelope phase of a laser pulse in a thin zinc selenide film has been experimentally demonstrated and confirmed by a numerical simulation. A pump–probe scheme has been implemented so that a pump pulse with a duration of about 1.5 field cycles, a central wavelength of 1.7 μm, and a stabilized carrier-envelope phase induces photoionization in a thin zinc selenide film. The probe pulse is scattered by the plasma, generating new phase-sensitive spectral components at the edges of its spectrum. The theoretical analysis has confirmed plasma nonlinearity as a mechanism for generating these components. The observed effect can be used to characterize the carrier-envelope phase of ultrashort pulses during the generation of high-order harmonics and sequences of attosecond pulses.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 1","pages":"8 - 13"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0021364024601489.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024601994
S. P. Kulik, S. N. Molotkov
{"title":"Hong–Ou–Mandel Interference in Quantum Optics, Monogamy of Entanglement, Nonorthogonality, and Untrusted Nodes","authors":"S. P. Kulik, S. N. Molotkov","doi":"10.1134/S0021364024601994","DOIUrl":"10.1134/S0021364024601994","url":null,"abstract":"<p>Quantum key distribution systems with an untrusted intermediate node described by the so-called measurement device independent (MDI) protocol have been actively studied in the last decade. In early works, it was only argued why such a quantum key distribution system ensures the security of distributed keys mentioning that the security proof of the MDI protocol, which was not presented, is similar to that for the basic Bennett‒Brassard 84 (BB84) protocol. <i>For this reason, despite the existing experimental implementations of the MDI quantum key distribution system, physical reasons for the protocol security are still questionable</i>. Such quantum key distribution systems provide a common key between two network nodes connected through the intermediate untrusted node, which does not require protection of the equipment on it, and an eavesdropper sees the entire operation of the equipment, including the results of the operation of photodetectors. In this work, the MDI protocol has been analyzed. It has been shown that the physical reasons for the protocol security are based on fundamental properties such as the interference of photons from different sources, monogamy of entanglement, and nonorthogonality of states. <i>A simple and explicit derivation is given showing the equivalence of the MDI and BB84 protocols and physical reasons for the identity of the corresponding expressions for the length of the final key.</i></p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 1","pages":"20 - 27"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0021364024601994.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S002136402460191X
V. P. Martovitskii, M. V. Nikitin, V. Ya. Pokrovskii
{"title":"Spinodal Decomposition of NbS3 Whiskers with Charge Density Waves","authors":"V. P. Martovitskii, M. V. Nikitin, V. Ya. Pokrovskii","doi":"10.1134/S002136402460191X","DOIUrl":"10.1134/S002136402460191X","url":null,"abstract":"<p>The grazing X-ray diffraction study of phase-II NbS<sub>3</sub> whiskers with charge density waves has shown that they exhibit pairs of broadened reflections from two close phases with the monoclinic angles β<sub>1</sub> and β<sub>2</sub> instead of single <span>((h0l))</span> peaks. The phase with the smaller monoclinic angle β<sub>1</sub> = 95.9°–97.2° is close in lattice parameters to phase I without charge density waves. Phase II with β<sub>2</sub> = 99.9°–100.0° has a reduced <b>b</b> lattice parameter along the strongest bond, which implies an increased concentration of sulfur vacancies in this phase compared to phase I. It has been concluded that the studied whiskers have underwent a spinodal decomposition with the redistribution of sulfur vacancies resulting in the alternation of phases in the (001) direction perpendicular to the layers. A satellite structure indicating the formation of a superlattice with a period of 35.2 nm in this direction is observed in the most structurally perfect whisker of phase II. The spinodal decomposition is combined with high internal stresses present in whiskers with a monoclinic lattice. The partial spinodal decomposition is also observed in some phase-I whiskers without charge density waves with the appearance of thin layers of phase IV and phase II with the monoclinic angle β = 104°. The existence of thin layers of phase II in the bulk of phase I in such samples exposed to a high-frequency voltage has been confirmed by the presence of Shapiro steps on current–voltage characteristics. Spinodal decomposition should be taken into account to describe the properties of NbS<sub>3</sub> whiskers nominally belonging to a certain polytype.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 1","pages":"38 - 45"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024602884
A. O. Savostianov, A. V. Naumov
{"title":"Phonon-Induced Spectral Line Broadening in Dye-Doped Glass in Terms of Resonant Vibrational Modes: Tetra-tert-Butylterrylene in Polyisobutylene","authors":"A. O. Savostianov, A. V. Naumov","doi":"10.1134/S0021364024602884","DOIUrl":"10.1134/S0021364024602884","url":null,"abstract":"<p>Previously [A.O. Savostianov, I.Yu. Eremchev, T. Plakhotnik, and A.V. Naumov, Phys. Rev. B <b>110</b>, 045430 (2024)], we have shown that the zero-phonon line broadening of single tetra-<i>tert</i>-butylterrylene molecules embedded in the matrix of amorphous polyisobutylene is a result of coupling with resonant vibrational modes arising due to the impurity effect on the host normal modes. However, the question remained whether this model would be compatible with the extensive single-molecule spectroscopy and photon echo data previously obtained for the same host/guest system. In the present work we demonstrate the high predictive power of the resonant mode model treated in the framework of the non-perturbative theory of electron–phonon coupling, and good agreement with all experimental data. Furthermore, for single-molecule data we find an unexpectedly large dispersion of the force constants for impurity molecules. To explain this dispersion, we propose a simple microscopic model that assumes fluctuations in the distance between the impurity molecule and its nearest surroundings.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 5","pages":"322 - 327"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-24DOI: 10.1134/S0021364024602033
V. I. Yudin, O. N. Prudnikov, A. V. Taichenachev, M. Yu. Basalaev, V. G. Pal’chikov, S. N. Bagayev
{"title":"Theory of Composite Ramsey Sequences of Radiofrequency Pulses beyond the Rotating Wave Approximation","authors":"V. I. Yudin, O. N. Prudnikov, A. V. Taichenachev, M. Yu. Basalaev, V. G. Pal’chikov, S. N. Bagayev","doi":"10.1134/S0021364024602033","DOIUrl":"10.1134/S0021364024602033","url":null,"abstract":"<p>We develop a theory of composite Ramsey sequences of rf pulses interacting with the Zeeman structure at the long-lived atomic level, beyond the rotating wave approximation. Such sequences are proposed in experiments to detect the violation of local Lorentz invariance [R. Shaniv, R. Ozeri, M.S. Safronova, S.G. Porsev, V.A. Dzuba, V.V. Flambaum, and H. Häffner, Phys. Rev. Lett. <b>120</b>, 103202 (2018)]. Based on Fourier analysis, we have shown that taking into account non-resonant contributions leads to a radical change in the dynamics of the quantum system (with respect to the rotating wave approximation) in the case when the number of Ramsey pulses exceeds several tens. As a result, the effectiveness of using such rf pulses sequences to test local Lorentz invariance has not yet been fully determined and requires additional research.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 1","pages":"28 - 32"},"PeriodicalIF":1.4,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-11DOI: 10.1134/S0021364024601398
S. O. Gurbatov, A. V. Shevlyagin, A. Yu. Zhizhchenko, E. B. Modin, A. A. Kuchmizhak, S. I. Kudryashov
{"title":"Photothermal Conversion and Laser-Induced Transformations in Silicon–Germanium Alloy Nanoparticles","authors":"S. O. Gurbatov, A. V. Shevlyagin, A. Yu. Zhizhchenko, E. B. Modin, A. A. Kuchmizhak, S. I. Kudryashov","doi":"10.1134/S0021364024601398","DOIUrl":"10.1134/S0021364024601398","url":null,"abstract":"<p>Si<sub>1 –</sub> <sub><i>x</i></sub>Ge<sub><i>x</i></sub> alloy nanoparticles with controlled composition have been obtained by nanosecond laser ablation of silicon–germanium targets in isopropanol. The synthesized product exhibits a polycrystalline structure and a unimodal size distribution with a predominant content of microparticles and retains the stoichiometry of the composition of the targets used for the synthesis. Nanothermometry with the detection and analysis of a Raman signal from single alloy nanoparticles with a size of ~200 nm demonstrates a threefold increase (in comparison with nanoparticles of pure silicon) in the heating efficiency of a nanomaterial with the composition Si<sub>0.45</sub>Ge<sub>0.55</sub> by 785-nm laser radiation falling into the first “transparency window” of biological tissues. Stimulated by continuous infrared radiation, the diffusion of silicon atoms to the surface (when heated to 650 K) and their oxidation lead to the gradual transformation of alloy nanoparticles into germanium clusters encapsulated in a SiO<sub><i>x</i></sub> matrix.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"119 12","pages":"910 - 916"},"PeriodicalIF":1.4,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JETP LettersPub Date : 2024-08-11DOI: 10.1134/S0021364024602689
V. P. Mineev
{"title":"Superconducting States in Metals with Toroidal Ordering","authors":"V. P. Mineev","doi":"10.1134/S0021364024602689","DOIUrl":"10.1134/S0021364024602689","url":null,"abstract":"<p>A theory of superconducting states in metals with toroidal symmetry is presented.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":"120 4","pages":"241 - 245"},"PeriodicalIF":1.4,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0021364024602689.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}