Article
Physics, Multidisciplinary
Sankar Das Sarma
Summary: Majorana particles, which are the same as their antiparticles, show promise for quantum computing in condensed matter systems. This article discusses the search for Majorana modes in semiconductor heterostructures and the limitations imposed by disorder. Majorana zero modes are emergent phenomena in topological superconductors, and this Perspective provides an overview of their physics, recent experimental progress, and future outlook for success.
Article
Physics, Multidisciplinary
A. P. Garrido, D. Zambrano, J. P. Ramos-Andrade, P. A. Orellana
Summary: We investigate the transport properties of a nanostructure composed of parallel double quantum dots coupled to normal contacts. Each quantum dot is connected to a topological superconducting nanowire with Majorana zero modes at its ends. The emergence of bound states and a transport suppression anomaly as a function of magnetic flux are found in symmetric configurations of the nanowires. The magnetic flux controls the projection of Majorana zero modes and bound states into the density of states and linear conductance, suggesting the potential manipulation of bound states by varying this parameter.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Materials Science, Multidisciplinary
Chun-Xiao Liu, Haining Pan, F. Setiawan, Michael Wimmer, Jay D. Sau
Summary: In this work, we propose a protocol for detecting the Majorana fusion rules in an artificial Kitaev chain and discuss the effects of realistic imperfections on the fusion outcomes. We also propose a fermion parity readout scheme and highlight the significance of these results for future experiments on detecting the non-Abelian properties of Majorana modes in a quantum dot chain.
Article
Physics, Multidisciplinary
P. Yu, J. Chen, M. Gomanko, G. Badawy, E. P. A. M. Bakkers, K. Zuo, V Mourik, S. M. Frolov
Summary: This study reports the observation of nearly quantized peaks close to the expected value by tunnel probes on both ends of a nanowire. However, the nearly quantized zero-bias peaks were only found localized to one end of the nanowire, raising doubts on whether they are Majoranas.
Article
Materials Science, Multidisciplinary
Sankar Das Sarma, Haining Pan
Summary: This paper discusses the general issue of confirmation bias in experiments verifying various theoretical topological quantization predictions, using the recently retracted work by Zhang et al. and the related data from the Delft experiment as examples. It also analyzes a more recent nanowire experiment, showing that disorder may lead to misinterpretation of trivial zero-bias peaks as topological Majorana modes.
Article
Multidisciplinary Sciences
Marco Valentini, Maksim Borovkov, Elsa Prada, Sara Marti-Sanchez, Marc Botifoll, Andrea Hofmann, Jordi Arbiol, Ramon Aguado, Pablo San-Jose, Georgios Katsaros
Summary: Hybrid semiconductor-superconductor devices have great potential for realizing topological quantum computing with Majorana zero modes. However, the detection of Majorana modes based on either tunnelling or Coulomb blockade spectroscopy is still disputable. In this study, we propose an experimental protocol that allows us to perform both types of measurement on the same hybrid island, effectively reducing ambiguities in Majorana detections.
Article
Materials Science, Multidisciplinary
Olesia Dmytruk, Mircea Trif
Summary: We investigate the behavior of a topological superconducting nanowire with gliding Majorana zero modes under the influence of a microwave cavity field. We find that the decay rate of the cavity is determined by the parity encoded by the Majorana zero modes and their motion, even without any direct overlap of their wave functions. This is due to the interference between the extended bulk states that overlap with both Majorana states, which allows for momentum-resolved microwave spectroscopy and is modified by the gliding motion. We also demonstrate that these nonlocal effects are resistant to moderate disorder and validate our numerical calculations with an analytical low-energy model. Our approach provides an alternative method to tunneling spectroscopy for probing the nonlocal features associated with Majorana zero modes in nanowires.
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
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
Materials Science, Multidisciplinary
Guan-Hao Feng, Hong-Hao Zhang
Summary: We propose a three-terminal structure to study robust signatures of Majorana zero modes. By observing the zero-bias differential conductance of the normal-metal lead at zero temperature, we can obtain information about Majorana braiding. The effect of thermal broadening is suppressed when the quantum dot is on resonance.
Article
Materials Science, Multidisciplinary
Haining Pan, Sankar Das Sarma
Summary: The study explores the properties of the superconductor-semiconductor nanowire hybrid Majorana platform in the presence of a deterministic slowly varying inhomogeneous chemical potential and a random quenched potential disorder. By calculating the tunnel conductance, the research examines the crossover among different mechanisms, with findings indicating the dominant role of random disorder in experiments.
Article
Materials Science, Multidisciplinary
L. Bittermann, C. De Beule, D. Frombach, P. Recher
Summary: We propose an alternative approach for detecting Majorana bound states (MBSs) by combining topological superconductivity with quantum optics. Using a superconducting pn junction containing a quantum dot, we tunnel-couple the MBSs to the electron level on the quantum dot and observe the emitted photons in the optical range. We analyze the polarization-resolved photon emission intensities and investigate the effects of MBS separation, spin states, and quasiparticle poisoning on the emission behavior.
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
Vivekananda Adak, Aabir Mukhopadhyay, Suman Jyoti De, Udit Khanna, Sumathi Rao, Sourin Das
Summary: A hybrid setup is proposed for chiral injection of electrons into the Majorana bound state, and an unexplored region in the phase space is proposed for the detection. Through comparison with different setups, the proposed structure demonstrates remarkable immunity from disorder-induced masking of the MBS.
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
Multidisciplinary Sciences
Koki Ono, Toshiya Higomoto, Yugo Saito, Shun Uchino, Yusuke Nishida, Yoshiro Takahashi
Summary: Cold atoms have become a versatile platform for the study of quantum transport phenomena, with recent research demonstrating an alternative experimental scheme using spin-dependent impurity scattering in a spinful Fermi gas. This new approach paves the way for atomtronics exploring spin degrees of freedom and emulating mesoscopic electronic devices.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Tatsuya Amitani, Yusuke Nishida
Summary: We investigate the equilibrium transport properties of massless Dirac fermions in space-time with torsion at finite temperature and chemical potential. The torsion couples with Dirac fermions as an axial gauge field in four dimensions. We calculate the current density in the presence of torsion and an external magnetic field using Pauli-Villars regularization, and find a locally induced equilibrium current similar to the chiral magnetic current. Such torsion can be realized in condensed matter systems along a screw dislocation line, where localized and extended current distributions are predicted to be relevant to Dirac and Weyl semimetals. Additionally, we compute the current density in the presence of torsion and a Weyl node separation, which is found to vanish despite being allowed by symmetry. We also discuss the contrasts of our results with previous work on torsion-induced currents.
Article
Physics, Multidisciplinary
Tomohiro Tanaka, Yusuke Nishida
Summary: The study shows that one-dimensional Bose and Fermi gases exhibit weak-strong duality under contact interactions, extending beyond thermodynamics to the frequency-dependent complex bulk viscosity.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Yusuke Nishida
Summary: Parallel electric and magnetic fields pump axial charge in Weyl semimetals until equilibrium is reached by intervalley relaxation. The resulting nonequilibrium steady state exhibits chiral magnetic and anomalous Hall effects, leading to unstable electromagnetic waves at low frequency and long wavelength. We demonstrate that the chiral magnetic instability is reflected as anomalous reflectance on the surface of pumped Weyl semimetal, with reflectance exceeding unity in a finite frequency range for circularly polarized light incident along the direction of Weyl node separation.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Tatsuya Amitani, Yusuke Nishida
Summary: Weyl semimetals with separated Weyl nodes exhibit massless relativistic fermions and their electromagnetic responses are studied using effective field theory and chiral kinetic theory. While the static chiral magnetic effect is cancelled, a dynamical magnetic field can generate an electric current along its direction. Dissipation and collective excitations coupled with Maxwell electromagnetic fields are also considered, predicting anisotropic generation of electromagnetic waves aligned with the direction of Weyl node separation.
Article
Physics, Fluids & Plasmas
Tomohiro Tanaka, Yusuke Nishida
Summary: This article investigates the thermal conductivity of a gas in one dimension, considering both two-body and three-body interactions. By summing up all contributions from low-order perturbation, a self-consistent equation is derived, revealing the dominant role of three-body interaction in thermal conductivity.
Article
Optics
Yusuke Nishida
Summary: This study investigates the frequency-dependent complex bulk viscosities of one-dimensional Bose and Fermi gases and reveals the properties of their Drude peaks in various limiting cases.
Article
Optics
Yusuke Nishida
Summary: It has been discovered that three charged particles can form bound states similar to Efimov states in different dimensions without any precise tuning. This finding is significant for the observation of excited states of three particles in hydrogen molecular ions and excitonic systems.
Article
Astronomy & Astrophysics
Yusuke Nishida
Summary: This study investigates the probability distribution of particle and antiparticle pairs produced via the Schwinger effect under the influence of a time-dependent electric field. The findings suggest that pair production is enhanced or suppressed in a medium for scalars or spinors respectively, due to Bose stimulation or Pauli blocking. Additionally, the annihilation of decelerated pairs is observed, along with the extraction of probability distributions in various scenarios using specialized statistics.
Article
Optics
Keisuke Fujii, Yusuke Nishida
Summary: Motivated by the failure of the kinetic theory for the bulk viscosity, this study revisits the shear viscosity and thermal conductivity of two-component fermions with zero-range interaction in two and three dimensions. The Kubo formula in the high-temperature limit is reduced to the linearized Boltzmann equation. By completing a microscopic derivation, it is found that the Prandtl number exhibits nonmonotonic behavior slightly below the constant value in the relaxation-time approximation.
Article
Optics
Yuta Sekino, Yusuke Nishida
Summary: The study focuses on local quantum field theories for one-dimensional Bose and Fermi gases, connected by Girardeau's Bose-Fermi mapping. It is found that while bosons require only a two-body interaction term, fermions need a marginally relevant three-body interaction. The presence of this three-body interaction leads to the appearance of a three-body contact in the energy relation for fermions, impacting momentum distribution and sum rules. Additionally, universal large-energy and momentum asymptotics for dynamic structure factor and single-particle spectral density are derived using the operator product expansion, applicable to any 1D scattering length at any temperature. Discussions also include the behavior of Tonks-Girardeau gas with hardcore repulsion and the Bose-Fermi correspondence in the presence of three-body attractions.
Article
Materials Science, Multidisciplinary
Takuya Furusawa, Keisuke Fujii, Yusuke Nishida
Summary: In this work, the effective field theory for the A phase of superfluid He-3 is constructed up to the next-to-leading order in the derivative expansion. By introducing background gauge fields and spatial metric, a hidden local symmetry known as nonrelativistic diffeomorphism is revealed, providing an additional constraint on the effective field theory and yielding a universal expression for the Hall viscosity in the A phase. It is found to be five orders of magnitude larger than that in the B phase under a magnetic field, making its experimental observation more feasible through measuring the induced elliptic polarization of sound waves.
Article
Physics, Fluids & Plasmas
Yu Nakayama, Yusuke Nishida
Summary: In three dimensions, the surface growth governed by the KPZ equation undergoes a roughening transition from smooth to rough phases with increasing attraction. Furthermore, critical bosons in three dimensions exhibit the Efimov effect, breaking the scale invariance down to a discrete one.
Article
Physics, Multidisciplinary
Yasuyuki Kato, Shang-Shun Zhang, Yusuke Nishida, C. D. Batista
PHYSICAL REVIEW RESEARCH
(2020)
Article
Optics
Sho Nakada, Shun Uchino, Yusuke Nishida