Article
Materials Science, Multidisciplinary
Meng-Qing Yu, Zhen-Gang Zhu, Gang Su
Summary: In this study, a Josephson junction setup consisting of intrinsic topological superconductors is proposed, in which the exchange operation of two Majorana zero modes (MZMs) can lead to a reversal of the single-electron tunneling current due to their non-Abelian statistics. This effect can be utilized to read out the initial qubit of the system, offering a way to demonstrate the non-Abelian statistical properties of MZMs.
Article
Materials Science, Multidisciplinary
Chuanchang Zeng, Girish Sharma, Sumanta Tewari, Tudor Stanescu
Summary: By examining recent experiments on Majorana zero modes in semiconductor-superconductor heterostructures, the authors critically analyze the quantization of zero-bias differential conductance as a potential signature of Majorana physics in the presence of disorder. Through numerical calculations, they find that the large topological region associated with a clean system breaks up into smaller islands as disorder strength increases. These islands with approximately quantized zero-bias conductance demonstrate the presence of partially separated Majorana modes. Decreasing disorder leads to the coalescence of these islands into large topological regions. Observing islands with near quantized zero-bias conductance provides evidence for Majorana physics and serves as a diagnostic tool for evaluating disorder strength.
Article
Materials Science, Multidisciplinary
Debashish Mondal, Arnob Kumar Ghosh, Tanay Nag, Arijit Saha
Summary: We theoretically investigate a practically realizable Floquet topological superconductor model based on a one-dimensional Rashba nanowire, which can generate multiple MEMs, and demonstrate the robustness of these MEMs in the presence of on-site time-independent random disorder potential.
Article
Materials Science, Multidisciplinary
Yi-Hua Lai, Sankar Das Sarma, Jay D. Sau
Summary: Despite recent progress in experimental observations of large zero-bias conductance peaks, it is still unclear whether Majorana modes have been observed. The existing experimental works lack stability of the putative Majorana mode features, indicating the absence of a topological phase. This paper introduces a dimensionless quality factor F to quantify the robustness of the zero-bias conductance peak height and proposes specific experimentally accessible measures for analyzing the stability of the observed peaks. The results show that Majorana modes are significantly more robust compared to nontopological peaks in the low-temperature limit and suggest that the quality factor F can be used to estimate the quality of topological qubits made from Majorana modes.
Article
Materials Science, Multidisciplinary
Donghao Liu, Zhan Cao, Xin Liu, Hao Zhang, Dong E. Liu
Summary: Efforts have been made to distinguish between Majorana zero modes (MZMs) and spatially separated quasi-Majorana modes (QMMs), both of which cause a quantized zero-bias peak in conductance measurement. A simple device utilizing a single nanowire was proposed to provide evidence of the topological Kondo effect in the topologically trivial phase with four QMMs, making it easier to distinguish Majorana and quasi-Majorana modes. Transport signatures are significantly different between the topological superconducting phase with MZMs and the topologically trivial phase with QMMs.
Article
Chemistry, Multidisciplinary
Jae-Joon Kim, Min Seok Park, Kyoung Seok Lee, Sang Hyun Joo, Jung Hoon Yoo, Dilip Bhoi, Byeong Hun Min, Kee Hoon Kim, Jinho Lee
Summary: In this study, the electronic structure of CLFA112 crystals was investigated at the atomic scale using low-temperature scanning tunneling microscopy (STM). Four different types of surface reconstructions were observed on CLFA112 crystals, and a clear superconducting gap was observed only at certain crevices on the surface. The FeAs layer exhibited a dispersing nematic modulation, and peculiar zero-bias conductance peaks were observed in the arsenic chain layer along with the influence of La dopants.
Article
Materials Science, Multidisciplinary
Kacper Wrzesniewski, Ireneusz Weymann
Summary: We theoretically study the quench dynamics of local magnetization in a hybrid Majorana-wire-quantumdot system. The dynamics show nonmonotonic dependence in the odd-occupation regime, and competitive behavior between ferromagnet and Majorana contributions when coupled to ferromagnetic leads. Multiple sign changes in magnetization can occur before relaxation to a new thermal value.
Article
Physics, Applied
Deepti Rana, Goutam Sheet
Summary: This research theoretically investigates the collective tunneling conductance between normal electrodes and a two-dimensional assembly of spin-orbit coupled superconducting nanowires. The odd-even rule and the effects of finite temperature, dissipation, and barrier potential on conductance profiles are discussed.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Deepti Rana, Goutam Sheet
Summary: In this study, we investigate the impact of tilting external magnetic field on the differential conductance of an array of uncoupled and weakly coupled wires. We present the phase diagram evolution with various control parameters, including the tilt angle of the magnetic field. By analyzing the field-angle dependence of the odd-even effect and its evolution over a large parameter space, we conclude that these results can be used to explore the zero-bias conductance peak arising from Majorana edge modes versus non-topological origin by tuning the magnetic-field angle in an array of Rashba-coupled semiconducting nanowires on a superconducting substrate.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Fei-Lei Xiong, Hon-Lam Lai, Wei-Min Zhang
Summary: A scheme is proposed to manipulate Majorana qubit states through electron transport and magnetic flux tuning in an Aharonov-Bohm interferometer setup. The Majorana qubit parity can be almost perfectly polarized by adjusting the bias and flipped by changing the sign of cross couplings. The qubit coherence exhibits phase rigidity due to the intrinsic particle-hole symmetry of the Majorana AB interferometer.
Article
Materials Science, Multidisciplinary
Chao Lei, Guru Khalsa, Jiangfeng Du, Allan H. MacDonald
Summary: The study shows that in cylindrical cross-section semiconductor quantum wires, weak coupling exists between quasi-one-dimensional subbands, low-energy quasiparticles near the Fermi energy are nearly completely spin polarized, and the number of electrons in the active subbands of topological states is less than 10.
Article
Physics, Applied
Pasquale Marra
Summary: Majorana bound states are quasiparticle excitations localized at the boundaries of a topologically nontrivial superconductor. They have special properties such as zero energy, charge neutrality, particle-hole symmetry, and spatial separation, making them ideal for the realization of topological quantum computation.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Multidisciplinary Sciences
Alexandre Huguet, Kacper Wrzesniewski, Ireneusz Weymann
Summary: The impact of spin effects on the nonequilibrium transport properties of a nanowire hosting Majorana zero-energy modes at its ends is examined. The study investigates the current, differential conductance, and current cross-correlations using the real-time diagrammatic technique. Results show that the presence of Majorana quasiparticles gives rise to unique features in all spin-resolved transport characteristics and is reflected in the current cross-correlations. The dependence of these features on various system parameters and the magnetic configuration of the system is also studied.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Multidisciplinary
Xu Lei, Li Pei-Ling, Lu Zhao-Zheng, Shen Jie, Qu Fan-Ming, Liu Guang-Tong, Lu Li
Summary: This paper reviews the electrical transport methods for detecting the presence of Majorana zero modes in topological superconductors. It discusses various experimental methods, such as electron tunneling spectroscopy, Coulomb blockade spectroscopy, and non-local conductance detection, as well as measurements of the AC Josephson effect and current phase relationships. Mechanisms for explaining the experimental data are also provided.
ACTA PHYSICA SINICA
(2023)
Article
Chemistry, Physical
Ning Cao, William Bro-Jorgensen, Xiaohong Zheng, Gemma C. Solomon
Summary: Quantum interference effects in conjugated molecules, specifically benzene, are well-understood and have been studied extensively. Recently, it has been discovered that even saturated molecules can exhibit destructive quantum interference effects, but the manifestation of orbital contributions in these molecules is still unclear. This study demonstrates that the quantum interference effects in conjugated molecules are distinct from those observed in saturated molecules, as shown by the quantum interference map. The destructive interference in saturated systems arises when contributions from a larger number of non-paired orbitals cancel each other, leading to more subtle and varied manifestations of destructive interference.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Multidisciplinary Sciences
H. Idzuchi, F. Pientka, K. -F. Huang, K. Harada, O. Gul, Y. J. Shin, L. T. Nguyen, N. H. Jo, D. Shindo, R. J. Cava, P. C. Canfield, P. Kim
Summary: This study reports unconventional supercurrent phase in van der Waals heterostructure Josephson junctions by coupling NbSe2 Ising Cooper pairs across a thin magnetic insulator Cr2Ge2Te6. The research demonstrates a doubly degenerate nontrivial JJ phase and proposes the potential of this structure to be utilized as a dissipationless component.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Jun Yong Khoo, Falko Pientka, Inti Sodemann
Summary: Metallic Fermi liquids and U(1) spin liquids exhibit the same universal transverse conductivity under specific conditions, behaving as metals in a certain regime despite appearing insulating in standard transport experiments. Fluctuations in transverse current result in a directly probed low-frequency magnetic noise, controlled purely by the geometry of the Fermi surface and independent of kinematic details of quasi-particles.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
K. Kavanagh, S. Dooley, J. K. Slingerland, G. Kells
Summary: In this study, we investigate the impact of particle pair creation and annihilation on the non-equilibrium steady state and Liouvillian gap of the quantum transverse XY model. By using operator quantization and a Majorana canonical basis, we demonstrate that the character of the gap is dependent on the anisotropy parameter and varies with the phase of the XY model, corresponding to a quantum phase transition.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
T. Kalsi, A. Romito, H. Schomerus
Summary: This study investigates the measurement-induced entanglement transition in quantum circuits built upon Dyson's three circular ensembles. By contrasting different ensembles, the study reveals the interplay between the local entanglement generation by the gates and the entanglement reduction by the measurements.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Correction
Physics, Multidisciplinary
J. Y. Khoo, Falko Pientka, Inti Sodemann Villadiego
NEW JOURNAL OF PHYSICS
(2022)
News Item
Physics, Multidisciplinary
Alessandro Romito
Summary: The interplay of quantum measurements and local interactions in many-body systems can lead to new out-of-equilibrium phase transitions. An experiment has demonstrated that quantum simulators can successfully detect these transitions.
Article
Materials Science, Multidisciplinary
Jun Yong Khoo, Falko Pientka, Patrick A. Lee, Inti Sodemann Villadiego
Summary: This study investigates the transverse electrical conductivity and magnetic noise of a two-dimensional U(1) spin liquid state. The results show that in the quasistatic regime, these responses have similar characteristics to that of a metal but are reduced by a factor determined by the ratio of orbital diamagnetic susceptibilities of the spinons and chargons.
Article
Physics, Multidisciplinary
Yunzhao Wang, Kyrylo Snizhko, Alessandro Romito, Yuval Gefen, Kater Murch
Summary: Measurement plays a crucial role in controlling quantum systems. Weak measurements, through their back action on the system, can enable coherent control and induce topological transitions in geometric phases. This connection reveals subtle topological features in measurement-based manipulation of quantum systems and opens up new avenues for measurement-enabled quantum control of many-body topological states.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
James Nelson, Luuk Coopmans, Graham Kells, Stefano Sanvito
Summary: We investigate the potential of supervised machine learning to propagate a quantum system in time. We find that for non-Markovian systems, their description requires the memory knowledge of past states, and the number of past states required grows exponentially with the number of spins and with the density of the system spectrum. Additionally, we demonstrate that neural networks can work as time propagators and can be concatenated in time to form an autoregression.
Article
Materials Science, Multidisciplinary
T. Boorman, M. Szyniszewski, H. Schomerus, A. Romito
Summary: We analyze the generation and destruction of entanglement in a one-dimensional quantum spin chain under locally noisy and disordered Hamiltonian using the concept of a measurement-induced entanglement transition. By continuously measuring the system, we induce a transition from volume to area-law scaling of the steady-state entanglement entropy. The critical measurement strength is systematically reduced by static background disorder, but the dependence on the strength of nonstatic noise is nonmonotonic. According to the extracted finite-size scaling exponents, the universality class of the transition is independent of the noise and disorder strength.
Article
Materials Science, Multidisciplinary
Shane Dooley, Graham Kells
Summary: Recent studies have shown that quantum many-body scarring can hinder the thermalization process of certain isolated quantum systems starting from specific initial states. In this paper, a class of spin chain models parameterized by a discrete variable l is constructed to control the strength of the dynamical constraint. It is found that by increasing the value of l, the constraint becomes weaker, resulting in fewer excluded states during the dynamics. By weakening the constraint to l >= 4, a more extreme version of quantum scarring is observed with an exponential growth of scar states as the system size increases.
Article
Materials Science, Multidisciplinary
Thomas Simons, Alessandro Romito, Dganit Meidan
Summary: The study analyzes the conductance of a one-dimensional topological superconductor periodically driven with different configurations of coupling to external leads, finding that the offset time of the zero-mode weight plays an important role in the discrepancy of conductance.
Article
Physics, Multidisciplinary
L. Coopmans, S. Dooley, I Jubb, K. Kavanagh, G. Kells
Summary: A local Hamiltonian with topological quantum order can be an excellent candidate for quantum memory due to its robust ground-state degeneracy, but caution is needed to avoid phase errors. The analysis explores how topological quantum order suppresses errors in the system and quantifies the correlation of spectral densities in different topological sectors. This is numerically verified through modeling an interacting p-wave superconducting wire.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Astronomy & Astrophysics
L. Borsten, I Jubb, G. Kells
Summary: It is shown that arbitrary sums of local observables will not signal, according to the expectations from relativistic quantum field theory. However, the measurement of the tensor product of commuting local observables can in fact signal, contrary to the widely held belief. This raises implications for the notion of measurement in relativistic quantum field theory.
Article
Materials Science, Multidisciplinary
Alexander Nikolaenko, Falko Pientka
Summary: In this study, we investigate the effect of vortices created by an external magnetic field in a type-II superconductor on the topological superconducting phase induced by the proximity coupling of one-dimensional systems. We identify different ways in which the protection of Majorana modes can be compromised and discuss strategies to mitigate these detrimental effects, which are also relevant to topological phases of proximitized quantum Hall edge states.
