Journal of Low Temperature Physics最新文献

{"title":"Development of Simultaneous Detection Method of Millimeter-Wave ESR and EDMR Signals of Phosphorus-Doped Silicon","authors":"H. Ito,&nbsp;Y. Shimizu,&nbsp;A. Ohashi,&nbsp;T. Omija,&nbsp;Y. Kurachi,&nbsp;K. Hayashi,&nbsp;Y. Ishikawa,&nbsp;A. Fukuda,&nbsp;X.-F. Liu,&nbsp;G. M. Gabriel,&nbsp;M. Mori,&nbsp;A. Oiwa,&nbsp;Y. Fujii","doi":"10.1007/s10909-026-03477-6","DOIUrl":"10.1007/s10909-026-03477-6","url":null,"abstract":"<div><p>We report the development of a measurement system enabling simultaneous detection of millimeter-wave electron spin resonance (ESR) and electrically detected magnetic resonance (EDMR) signals in lightly phosphorus-doped silicon (Si:P). Such simultaneous detection is motivated by the need to clarify spin-dependent transport and dynamic nuclear polarization mechanisms in high-magnetic-field and low-temperature conditions relevant to Si:P-based quantum computing architectures. A Si:P sample was mounted on a Fabry–Pérot resonator and was equipped with comb-shaped electrodes optimized for millimeter-wave transmission, allowing ESR excitation while monitoring the current through the sample under optical illumination. Using a 130 GHz millimeter-wave source, we successfully observed ESR absorption signals and corresponding EDMR responses simultaneously at temperatures around 5 K. The EDMR signals exhibited sharper linewidths compared to ESR. These results demonstrate the feasibility of combined ESR–EDMR measurements and provide a foundation for future studies on coupled electron–nuclear spin dynamics, including the simultaneous observation of ESR and EDMR.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 6","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"On the Superconducting Phases of (hbox {UTe}_2)","authors":"V. I. Marchenko,&nbsp;L. A. Melnikovsky","doi":"10.1007/s10909-026-03471-y","DOIUrl":"10.1007/s10909-026-03471-y","url":null,"abstract":"<div><p>The anomalous triple point discovered in superconducting <span>(hbox {UTe}_2)</span> may indicate a gauge invariance breaking in the high-pressure phase, manifesting as Bose condensation of bound states of eight or even more electrons. \u0000</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 6","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Cryogenic CMOS Control Circuits for Scalable Quantum Computing Architecture","authors":"Neeraj kumar,&nbsp;Aijaz Mehdi Zaidi,&nbsp;Balwinder Raj,&nbsp;Dushyant kumar","doi":"10.1007/s10909-026-03481-w","DOIUrl":"10.1007/s10909-026-03481-w","url":null,"abstract":"<div><p>The development of scalable quantum computing requires the development of classical control electronics capable of operating reliably under cryogenic conditions. Quantum processors currently depend on room-temperature control systems, which need multiple interconnect cables to connect their equipment. This study investigates cryogenic complementary metal–oxide–semiconductor (CMOS) circuits as a promising solution for scalable quantum computing control systems. The behaviour of CMOS devices at cryogenic temperatures is analysed in terms of carrier mobility, threshold voltage, leakage current, and switching characteristics, which all strongly influence circuit performance. The proposed system uses a hierarchical cryogenic control architecture, which distributes digital control and signal-generation blocks across different temperature stages to achieve reduced wiring overhead and improved system scalability. The researchers created a three-stage cryogenic CMOS ring oscillator to study how temperature affects oscillation frequency and propagation delay and power consumption and signal stability. This work presents a simulation-based analysis of cryogenic CMOS circuits using temperature-dependent device models. Cryogenic temperatures provide significant advantages, including increased carrier mobility for faster switching and reduced leakage current for lower static power, but they also introduce challenges such as threshold-voltage shifts, device variability, and modelling limitations that require cryogenic-aware design. The research demonstrates that cryogenic CMOS circuits function as efficient systems, which deliver compact control electronics that use minimal energy while maintaining scalability for superconducting qubit-based quantum computing systems.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 6","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Superconducting Triple Point in UTe₂: Thermodynamics and Symmetry","authors":"L. A. Melnikovsky","doi":"10.1007/s10909-026-03470-z","DOIUrl":"10.1007/s10909-026-03470-z","url":null,"abstract":"<div><p>Three lines of second-order phase transitions between the normal phase and two distinct superconducting phases meet at a single point on the phase diagram of UTe<span>(_2)</span> [1]. Although it is commonly believed otherwise, such triple points are not subject to thermodynamic constraints. In [12], the phase diagram is interpreted within Landau theory in terms of two superconducting order parameters with different gauge symmetries. Such an interpretation is unique under the assumption of spatial uniformity.\u0000</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 6","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"An Artificial Bosonic-Bath Quantum Simulator Based on Electrons on Liquid Helium Coupled to Passive LC Arrays","authors":"Airat G. Kiiamov,&nbsp;Dmitrii A. Tayurskii","doi":"10.1007/s10909-026-03479-4","DOIUrl":"10.1007/s10909-026-03479-4","url":null,"abstract":"<div><p>We propose and analyse a passive artificial-boson architecture in which a two-dimensional electron system on liquid helium is coupled electrostatically to a microstructured array of resonant LC cells. The aim of the work is not to claim an already established superconducting state, but to derive a controlled feasibility map for LC-mediated retarded attraction in an exceptionally clean electronic platform. The charge degrees of freedom of the LC array are quantized and integrated into a Fröhlich-type effective interaction whose strength is governed by the full electrostatic transfer function of the electron–helium–metal structure. We show that the frequently useful long-wavelength expression gives only an upper electrostatic scale and must not be interpreted as a physical Eliashberg coupling without finite-pad form factors, screening, disorder, and losses. We therefore formulate the pairing criterion in terms of a transfer-function-limited dimensionless coupling and provide conservative numerical scales for the density, Fermi temperature, Wigner crystallization temperature, artificial-mode energy, and resonator linewidth. This analysis makes clear that the experimentally natural low-density regime is generally not a weak-coupling degenerate Fermi liquid: it is instead close to a classical Coulomb liquid or Wigner-solid regime. Quantum-degenerate mobile regimes require either higher density or confinement engineering, whereas the natural low-density limit is better viewed as a non-adiabatic strong-coupling crossover problem. The role of lithographic disorder and inter-cell crosstalk is reconsidered together with dissipative broadening, distinguishing useful coherent bandwidth engineering from loss-induced decoherence. Finally, we discuss experimental observables, emphasizing that a doubled effective charge in shot noise cannot by itself prove pairing in a device without superconducting contacts. The resulting framework identifies the conditions under which passive LC substrates may serve as tunable quantum simulators of retarded interactions, polaron formation, and possible BCS–BEC crossover physics.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 6","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149338748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Angular Dependence of Hall Effect and Magnetoresistance of the Nodal-Line Semimetals CaAg0.9Pd0.1P","authors":"Naoki Matsubara,&nbsp;Rikizo Yano,&nbsp;Haruka Taniguchi,&nbsp;Yoshihiko Okamoto,&nbsp;Satoshi Kashiwaya","doi":"10.1007/s10909-026-03474-9","DOIUrl":"10.1007/s10909-026-03474-9","url":null,"abstract":"<div><p>CaAgP has been accepted as a nodal-line semimetal exhibiting unusual physical properties, such as anomalous magnetoresistance, high-mobility electron carriers (HMEC), and surface superconductivity. In this study, we performed angular-dependent Hall resistivity and magnetoresistance measurements on Pd-doped CaAgP single crystals, with the applied current oriented parallel (<i>I</i> // <i>c</i>) and perpendicular (<i>I</i> ⟂ <i>c</i>) to the <i>c</i>-axis. Analysis of the Hall resistivity using a two-carrier model reveals that the electron contribution was larger for the <i>I</i> ⟂ <i>c</i> configuration, which was more seriously influenced by the (001) surface. Moreover, the Hall resistivity exhibits different angular dependences between the high- and low-field regimes. These findings indicate that the HMEC are highly concentrated on the (001) surface. Meanwhile, the angular dependences of the magnetoresistance are interpreted as arising from the competition between two-dimensional weak antilocalization and three-dimensional weak localization, consistent with the presence of a torus-shaped nontrivial Fermi surface. Taken together, the Hall resistivity and magnetoresistance results demonstrate that Pd-doped CaAgP is a nodal-line semimetal hosting drumhead surface states on the (001) surface.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 6","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Thermal Conductivity of Various CFRPs from 100 mK to 20 K","authors":"Valentin Sauvage","doi":"10.1007/s10909-026-03469-6","DOIUrl":"10.1007/s10909-026-03469-6","url":null,"abstract":"<div><p>Carbon-fiber-reinforced polymers (CFRPs) are among the most promising structural materials for aerospace applications, particularly for systems operating at cryogenic temperatures, where high strength, low mass, and low thermal conductivity are essential. In this work, the thermal conductivity of a set of CFRP samples: T300 (67% 0<span>(^circ )</span>), T700 (62% 0<span>(^circ )</span>), HS40 (67% 0<span>(^circ )</span>/0<span>(^circ )</span>/0<span>(^circ )</span>/90<span>(^circ )</span>), HS40 (62% 0<span>(^circ )</span>/0<span>(^circ )</span>/0<span>(^circ )</span>/90<span>(^circ )</span>), M55J (0<span>(^circ )</span>), HS40 (67% 0<span>(^circ )</span>), HS40 (62% 0<span>(^circ )</span>), IMA (0<span>(^circ )</span>), and IMA (90<span>(^circ )</span>), was measured over the temperature range 100 mK to 20 K. Thermal conductivities were extracted using a new analysis method developed. The resulting temperature-dependent behavior for each sample is presented and compared with the existing literature.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 5","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Generic Thermodynamics of Condensates with Extremely Small Superfluid Density: Application to (hbox {UTe}_2) and Hidden Second Phase Transition","authors":"Kazushige Machida","doi":"10.1007/s10909-026-03467-8","DOIUrl":"10.1007/s10909-026-03467-8","url":null,"abstract":"<div><p>Motivated by recent experimental findings on <span>(hbox {UTe}_2)</span> via NMR and specific-heat experiments, we theoretically explore the thermodynamic signatures of condensates with small superfluid density and characterize their physical properties. We identify a hidden superconducting phase <span>(A_2)</span> composed of spin-up Cooper pairs at lower temperature (<i>T</i>) and field (<i>H</i>) under ambient pressure of <span>(hbox {UTe}_2)</span> and show that <span>(A_2)</span> reappears at higher <i>H</i> for all three principal field directions, <i>a</i>-, <i>b</i>-, and <i>c</i>-axis. The phase-transition lines from the <span>(A_1)</span> phase with spin-down pairs to the <span>(A_2)</span> phase in the <i>H</i>-<i>T</i> plane are horizontal and common to all three axes. With increasing magnetic field, the magnetic energy gain of the spin-up pairs is greater than that of the spin-down pairs. This multiple-phase diagram is extended to these under pressure (<i>P</i>), resulting in a simple picture based on non-unitary spin-triplet pairing symmetry <span>(^3B_{3u})</span>, which enables us to consistently capture the evolution of the superconducting phases throughout the entire <i>H</i>-<i>T</i>-<i>P</i> phase space.\u0000</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 5","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Performance Investigation of a Quantum Thermoacoustic Heat Pump Micro-Cycle","authors":"Decheng Li,&nbsp;Qing E","doi":"10.1007/s10909-026-03468-7","DOIUrl":"10.1007/s10909-026-03468-7","url":null,"abstract":"<div><p>In this work, quantum mechanics theory was applied to the thermoacoustic heat pump, and a quantum mechanical model within a one-dimensional harmonic potential well, namely the quantum thermoacoustic heat pump micro-cycle (TAHPMC), was constructed. Based on this model, the coefficient of performance <span>(text{C}text{O}text{P})</span> and heating rate <span>(H)</span> of the thermoacoustic heat pump were derived, and dimensionless form <span>({H}^{*})</span> of <span>(H)</span> was defined for further analysis. The effects of the characteristic width of the potential well <span>(A)</span> and the width ratio <span>(y)</span> on these two parameters were systematically analyzed. To achieve synergistic optimization of the two performance indicators, an optimization objective function <span>(Omega)</span> was established. Through numerical optimization, the parameter interval that optimizes the comprehensive performance of <span>(text{C}text{O}text{P})</span> and <span>({H}^{*})</span> was identified, and it was proved that the reduction in heat leakage can significantly improve the heating capability of the thermoacoustic heat pump.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 5","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

{"title":"Effects of Bridges on AC Losses in Bi-2212 Multifilamentary Wire Based on 3D Simulations","authors":"Xu Wang,&nbsp;Hong Zhang,&nbsp;Wei Chen,&nbsp;XinSheng Yang,&nbsp;JunXin Luo,&nbsp;XueQian Liu,&nbsp;ShengNan Zhang,&nbsp;Jing Jiang","doi":"10.1007/s10909-026-03459-8","DOIUrl":"10.1007/s10909-026-03459-8","url":null,"abstract":"<div><p>High-temperature superconductors such as REBa₂Cu₃O_7−x<b> (</b>REBCO) tape conductor and Bi₂Sr₂CaCu₂O_x (Bi-2212) superconducting round wires exhibit great promise for future high-field magnet applications due to their advantages including high-field performance and high current-carrying capacity. Among these, Bi-2212 demonstrates significant advantages in the design of magnets for accelerators, NMR, and similar applications, owing to its isotropic characteristics. After heat treatment, bridges formed between the filaments of the Bi₂Sr₂CaCu₂O_x superconducting round wires. The impact of these bridges on the current-carrying capacity has not been fully studied and understood, especially the influence of such bridges on the AC loss remains unclear. In this paper, based on the three-dimensional finite element method, numerical simulation studies are conducted using the Kim model and the power law model. Within the frequency range of 50 to 100,000 Hz, and under the condition where the transport current is<i> I</i>_c multiplied by 0.1 to 1, the influence mechanism of the bridging and connection degree of the Bi-2212 filaments on the AC loss is investigated. When the transport current is less than 0.5 times the value of<i> I</i>_c, compared with the ideal Bi-2212 multifilamentary wire without bridging, the bridges hardly affect the magnitude of AC loss. However, when the transport current is greater than 0.5 times value of<i> I</i>_c, the AC loss will rises significantly. As the volume of the bridge structure increases, the AC loss will increase by almost more than 10 times. Furthermore, when large current is transmitted in the low-frequency range, the AC loss will significantly increase due to the presence of the bridge. However, as the frequency increases, the AC loss gradually decreases and eventually approaches the AC loss value of the ideal Bi-2212 multifilamentary wire without the bridges. It suggests that for large current transmission, high frequency can alleviate the impact on the bridge.</p></div>","PeriodicalId":641,"journal":{"name":"Journal of Low Temperature Physics","volume":"222 5","pages":""},"PeriodicalIF":1.2,"publicationDate":"2026-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}