Article
Chemistry, Multidisciplinary
Felix Luepke, Dacen Waters, Anh D. Pham, Jiaqiang Yan, David G. Mandrus, Panchapakesan Ganesh, Benjamin M. Hunt
Summary: In this study, the topological nature of twisted bilayer WTe2 was investigated using scanning tunneling microscopy and spectroscopy (STM/STS). The characteristic spectroscopic signatures of the quantum spin Hall edge states were observed at the edges of the twisted bilayer. Through calculations, it was found that the topology of WTe2 bilayers can be engineered by adjusting the twist angle and interlayer interactions.
Article
Multidisciplinary Sciences
Sein Park, Wonjun Lee, Seong Jang, Yong-Bin Choi, Jinho Park, Woochan Jung, Kenji Watanabe, Takashi Taniguchi, Gil Young Cho, Gil-Ho Lee
Summary: Engineering quantum states through light-matter interaction has created a new paradigm in condensed-matter physics. In this study, steady Floquet-Andreev states were successfully generated in graphene Josephson junctions and their spectral characteristics were quantitatively analyzed. This research provides a foundation for understanding and engineering non-equilibrium quantum states in nanodevices.
Article
Materials Science, Multidisciplinary
Oguz Turker, Kun Yang
Summary: We derive the effective theories for quantum Hall droplets with attractive interaction and find that they resemble string theories. The generalization to interfaces between different quantum Hall liquids is also discussed.
Article
Chemistry, Physical
Gad Koren, Anna Eyal, Leonid Iomin, Yuval Nitzav
Summary: A new type of transport in oxygen poor Nd0.8Sr0.2NiO3-delta films has been observed, featuring variable range hopping at high temperatures and a novel tunneling behavior at low temperatures characterized by a Josephson-like tunneling junction with serial resistance. The phenomenon is attributed to coupling between superconductive surfaces of the grains in Oxygen poor films via the insulating grain boundaries, resulting in SIS junctions in series with the normal resistance of the grains themselves. The similarity of the conductance spectra to the tunneling junction characteristic with Josephson-like current supports the existence of superconductivity in the samples.
Article
Materials Science, Multidisciplinary
Lucila Peralta Gavensky, Gonzalo Usaj, C. A. Balseiro
Summary: We studied the transport properties of a voltage-biased Josephson junction coupled via the edges of a quantum Hall sample, finding that resonant multiple Andreev reflection processes enhance quasiparticle transmission and enable spectroscopy of one-way edge modes in these hybrid devices.
Article
Physics, Multidisciplinary
Enock Oladimeji, Solomon Owolabi, Joshua Adeleke
Summary: In this study, a quantum heat engine based on the strongly non-linear quantum oscillator described by the Poschl-Teller model is examined, showing similarities to a Carnot cycle. The efficiency of this quantum engine is derived and it exhibits analogous behavior to classical thermodynamic engines.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
Tarik P. Cysne, Marcio Costa, Luis M. Canonico, M. Buongiorno Nardelli, R. B. Muniz, Tatiana G. Rappoport
Summary: Recent research has shown that TMD monolayers in the 2H structural phase exhibit large orbital Hall conductivity plateaus within their energy band gaps, with their spin Hall conductivities vanishing. The valley Hall effect in these systems also generates a transverse flow of orbital angular momentum, making it experimentally challenging to distinguish between the two effects. However, it has been found that a 2H-MoS2 bilayer can act as an orbital Hall insulator, showing a significant orbital Hall effect in the absence of both spin and valley Hall effects.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Andrey Akhmeteli
Summary: In 1952, Schrödinger discovered that a scalar complex wave function can be made real through a gauge transformation. The author recently demonstrated that one real function is sufficient to describe matter in the Dirac equation in any electromagnetic or Yang-Mills field. This indicates a symmetry between positive and negative frequencies, particles and antiparticles. Based on this, the author proposed describing one-particle wave functions as plasma-like collections of numerous particles and antiparticles. This study provides a criterion for approximating continuous charge density distributions with quantized charge using partial Fourier sums, and presents an example of such approximation using the homotopy continuation method.
Article
Physics, Multidisciplinary
Izzet Sakalli, Esra Yoruk
Summary: This article studies the Hawking radiation of Schwarzschild black hole within the bumblebee gravity model. By introducing alternative coordinate systems and incorporating the Generalized Uncertainty Principle, the dependency of Hawking radiation temperature on coordinate systems is examined. The modified equation characterizing particle behavior near the event horizon is derived, and the modified temperature of the SBHBGM is obtained by calculating the tunneling probability using the modified action.
Article
Nanoscience & Nanotechnology
Yang Cheng, Sisheng Yu, Menglin Zhu, Jinwoo Hwang, Fengyuan Yang
Summary: The study reports the observation of high-temperature topological Hall signal in Mn3Sn/Pt bilayers, likely attributed to the stabilization of topological spin textures enabled by the strong spin-orbit coupling of the Pt overlayer and the Dzyaloshinskii-Moriya interaction at the Mn3Sn/Pt interface.
Article
Materials Science, Multidisciplinary
Qiang Cheng, Qing Yan, Qing-Feng Sun
Summary: Our study reveals that the Josephson effect in spin-triplet superconductor-quantum anomalous Hall insulator-spin-triplet superconductor junctions strongly depends on the orientations of the d vectors in superconductors, showing different effects for different configurations.
Article
Optics
F. Binanti, K. Furutani, L. Salasnich
Summary: The study investigates the dynamics of bosonic atoms in elongated Josephson junctions and reveals an intrinsic coupling between the Josephson mode and sound modes. This coupling results in damped and stochastic dynamics for the Josephson degree of freedom. The research also explores the evolution of relative-phase and population-imbalance fluctuations of the Josephson mode and their oscillating thermalization to equilibrium.
Article
Materials Science, Multidisciplinary
R. S. Akzyanov, A. L. Rakhmanov
Summary: In this study, the physics of the Josephson effect in odd-parity nematic superconductors is investigated. It is found that the interaction between nematicity and crystallographic axes in the superconductors leads to an unusual Josephson effect, which can be observed without any magnetization and exhibits an anomalous Josephson Hall effect.
Article
Engineering, Multidisciplinary
R. R. Nigmatullin, A. K. Rybin, K. S. Nepeina, P. A. Kaznacheev
Summary: Non-Orthogonal Combined Fourier Analysis of the Smoothed Signals (NOCFASS) is a new technique that helps extract the reduced/invariant spectrum from the total Fourier-spectrum of natural processes like seismic ambient noise. The authors demonstrate the effectiveness of this method in signal processing at the Ukok-2 point in Tien Shan. The selected spectrum, with eliminated high-frequency components, is considered as an invariant spectrum containing only basic low-frequency modes, which is useful for detecting different random factors that disturb the TLS behavior.
Article
Physics, Multidisciplinary
Gwang-Hee Kim
Summary: The study investigates the quantum-classical crossover of the escape rate in a nanomagnetic Josephson phi(0) junction using the spin-coherent-state path integral method. The nonlinear perturbation approach is utilized to identify the boundary between the first- and second-order crossovers, with the region of the first-order crossover significantly suppressed by bias current and external magnetic field. These findings can be tested using existing experimental techniques.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2021)
Article
Physics, Multidisciplinary
Alexander Lau, Timo Hyart, Carmine Autieri, Anffany Chen, Dmitry Pikulin
Summary: Flat-band systems provide an ideal platform to study the competition and possible coexistence of superconductivity and magnetism, but two-dimensional systems face limitations in low-temperature phase stability. By strain engineering in topological nodal-line semimetals to generate three-dimensional flat bands, the conundrum of combining flat-band phases with stable order at high temperatures can be solved.
Article
Physics, Multidisciplinary
Vladislovas Cizas, Liudvikas Subacius, Natalia V. Alexeeva, Dalius Seliuta, Timo Hyart, Klaus Koehler, Kirill N. Alekseev, Gintaras Valusis
Summary: This study reports the first observation of dissipative parametric generation in a semiconductor superlattice, where the periodic variation of negative differential velocity excites slow electrostatic waves and enhances the gain coefficient.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Alexander Lau, Sebastiano Peotta, Dmitry Pikulin, Enrico Rossi, Timo Hyart
Summary: Motivated by experimental progress, this study investigates the effects of energy band dispersion and quantum geometry on the disorder-induced suppression of superfluid weight in superconductors. Surprisingly, it is found that the disorder-dependence of the superfluid weight is universal across different models, independent of quantum geometry and flatness of dispersion. This suggests that flat-band superconductors are as resilient to disorder as conventional superconductors.
Article
Physics, Multidisciplinary
V. Fernandez Becerra, Mircea Trif, Timo Hyart
Summary: We study the properties of semiconducting nanowires with induced superconductivity and ferromagnetism, and find that spin pumping is quantized in the topologically nontrivial phase while charge pumping is not. In long topologically nontrivial nanowires, there is a one-to-one correspondence between quantized conductance, entropy change, and spin pumping. The observation of correlated and quantized peaks in conductance, entropy change, and spin pumping would provide strong evidence of Majorana zero modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Valerii Kachin, Teemu Ojanen, Jose L. Lado, Timo Hyart
Summary: In two-dimensional superconductors, electron-electron interactions can enhance or reduce the topological energy gaps and cause topological phase transitions. However, statistically, the interactions have no effect on the realized Chern numbers and typical magnitudes of the topological gaps. The interactions substantially increase the likelihood of the largest topological gaps in the tails of the energy gap distribution in comparison to the noninteracting case.
Article
Materials Science, Multidisciplinary
Wojciech Brzezicki, Matti Silveri, Marcin Plodzien, Francesco Massel, Timo Hyart
Summary: Dissipation in open systems extends the symmetries of Hamiltonians and allows the existence of novel non-Hermitian topological phases with long-living end states. In this study, we propose a reservoir-engineered transmon chain that exhibits a non-Hermitian topological quantum phase through spatial modulation of dissipation. By solving the many-body Lindblad master equation, we demonstrate that the topological end modes and the associated phase transition can be observed in reflection measurements with experimentally realistic parameters. Furthermore, we show that genuine quantum effects, such as long-range quantum entanglement, can be generated passively in this system.
Article
Materials Science, Multidisciplinary
Nguyen Minh Nguyen, Giuseppe Cuono, Rajibul Islam, Carmine Autieri, Timo Hyart, Wojciech Brzezicki
Summary: Experiments on HgTe/CdTe and InAs/GaSb heterostructures, which are potential candidates for quantum spin Hall insulators, reveal the existence of additional edge states besides the topologically protected helical edge modes. Using first-principles calculations, an effective tight-binding model is derived for these materials, showing that the additional edge states are sensitive to edge termination. These states originate from a minimal model supporting flat bands with nontrivial quantum geometry and give rise to polarization charges at the edges.
Article
Physics, Multidisciplinary
Aleksander Sanjuan Ciepielewski, Jakub Tworzydlo, Timo Hyart, Alexander Lau
Summary: In this study, we investigate the relationship between the four-terminal conductance and the Fermi surface topology in mesoscopic, ballistic samples of small-angle twisted bilayer graphene. We establish a correspondence between features in the wide-junction conductance and the presence of Van Hove singularities in the density of states. Additionally, we identify other transport features such as pressure-tunable minimal conductance, conductance peaks coinciding with nonsingular band crossings, and unusually large conductance oscillations as a function of system size.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Tania Paul, V. Fernandez Becerra, Timo Hyart
Summary: This study investigates the band-inverted electron-hole bilayers in InAs/GaSb and demonstrates the time-reversal symmetry broken phase caused by Coulomb interactions. The transport properties in this phase are consistent with recent experimental observations. Additionally, a quantum transport study on a Corbino disk reveals unambiguous transport signatures of the broken phase.
Article
Materials Science, Multidisciplinary
Tania Paul, V. Fernandez Becerra, Timo Hyart
Summary: It is proposed that band-inverted electron-hole bilayers can undergo a phase transition to a quantum spin Hall insulator phase in the presence of increasing electron and hole densities. This study shows that Majorana zero modes can exist in the time-reversal symmetry broken phase of the system with proximity-induced superconductivity, even in the absence of a magnetic field. The analysis reveals that these zero modes can be detected through measurements of a 4π Josephson current in superconductor/time-reversal symmetry broken insulator/superconductor Josephson junctions, and the gate voltage dependence of the spontaneous time-reversal symmetry breaking order parameter can be utilized for Majorana fusion-rule detection.
Article
Physics, Multidisciplinary
Timo Hyart, J. L. Lado
Summary: This study demonstrates that non-Hermitian many-body topological modes can be achieved in a quantum dot chain through gate-tunable modulation of dissipation. The results show that these topological modes are robust even in the presence of strong interactions, highlighting the resilience of non-Hermitian topology to electronic interactions.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Xiang Hu, Timo Hyart, Dmitry I. Pikulin, Enrico Rossi
Summary: Flat-band systems provide a promising platform for studying exotic collective ground states. In this study, using double-twisted bilayer graphene heterostructures as an example, the stability of the exciton condensate (EC) phase is investigated. It is found that for realistic interaction strengths, the EC phase is favored over other phases when the bilayers have opposite doping. The quantum metric of the Bloch wave functions plays a critical role in stabilizing the EC phase.
Article
Materials Science, Multidisciplinary
Nguyen Minh Nguyen, Wojciech Brzezicki, Timo Hyart
Summary: The study reveals the existence of symmetry-protected topological states in SnTe nanowires, exhibiting distinct properties under different conditions. In the presence of superconductivity, SnTe nanowires show Bloch Majorana modes with quantized thermal conductance. Introducing an inversion-symmetry-breaking field results in topologically protected localized Majorana zero modes at the ends of the nanowire.
Article
Materials Science, Multidisciplinary
V. Fernandez Becerra, Mircea Trif, Timo Hyart
Summary: Spin pumping involves injecting spin currents into a nonmagnetic material due to the precession of a neighboring ferromagnet, resulting in quantized and interconnected charge, spin, and heat pumping in a device with topological effects. The interplay of two topological effects, including topologically protected perfect Andreev reflection, allows the device to operate as a robust charge, spin, and heat transistor.
Article
Physics, Multidisciplinary
V. Vadimov, T. Hyart, J. L. Lado, M. Mottonen, T. Ala-Nissila
Summary: In this study, zero modes emerge in a many-body system without gauge symmetry breaking and in the absence of superconducting order, showing that robust Majorana-like zero modes may appear in a many-body system with no single-particle analogs.
PHYSICAL REVIEW RESEARCH
(2021)
