Article
Materials Science, Multidisciplinary
Ankur Das, Sumathi Rao, Yuval Gefen, Ganpathy Murthy
Summary: In a Quantum Hall system or other systems with neutral modes, it is possible to reconstruct a direct current charge current non-locally using neutral modes.
Article
Materials Science, Multidisciplinary
N. Moreau, B. Brun, S. Somanchi, K. Watanabe, T. Taniguchi, C. Stampfer, B. Hackens
Summary: Observations of electron-hole asymmetry in transport through graphene devices at high magnetic field challenge prevalent models of the graphene quantum Hall effect. The presence of upstream modes and local doping in the vicinity of electrical contacts leads to a different topological breakdown for electrons and holes, explaining the observed asymmetry.
Article
Materials Science, Multidisciplinary
Jukka Vayrynen, Moshe Goldstein, Yuval Gefen
Summary: The edges of quantum Hall phases exhibit a variety of exotic modes, including neutralons, which are chargeless anyons with semion statistics. These neutral particles can be experimentally accessed, making their study and manipulation intriguing and challenging. This article focuses on the strongly interacting regime of neutralons, where a quarteting mechanism replaces conventional pairing and leads to neutralon superconductivity. The manifestations of this effect are discussed, along with the potential for observing interference of the accompanying charged anyons.
Article
Multidisciplinary Sciences
Ying Wang, Vadim Ponomarenko, Zhong Wan, Kenneth W. West, Kirk W. Baldwin, Loren N. Pfeiffer, Yuli Lyanda-Geller, Leonid P. Rokhinson
Summary: Experimental observation in the fractional quantum Hall regime shows that the current carried by hDWs is significantly smaller than predicted by the naive model. Theoretical analysis using Luttinger liquid theory reveals a redistribution of currents between quasiparticle charge, spin, and neutral modes, leading to the reduction of the hDW current. Including spin-non-conserving tunneling processes reconciles theory with experiment and confirms the emergence of spin modes necessary for the formation of fractional topological superconductivity.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Zhaoyu Han, Jing-Yuan Chen
Summary: We construct a class of lattice Hamiltonians that can be solved controllably in their low-energy sectors through a combination of perturbative and exact techniques, circumventing the KapustinFidkowski no-go theorem. Our construction is generalizable.
Article
Physics, Multidisciplinary
Ruihua Fan, Rahul Sahay, Ashvin Vishwanath
Summary: This paper proposes a new formula for extracting the quantum Hall conductance from a gapped wave function. The formula applies to many-body systems that conserve particle number and exhibits all the formal properties of the Hall conductance. Furthermore, evidence from conformal field theory supports the relation between the formula and the Hall conductance. Numerical verification is also provided with an example of a noninteracting Chern band.
PHYSICAL REVIEW LETTERS
(2023)
Review
Physics, Multidisciplinary
D. E. Feldman, Bertrand Halperin
Summary: This article discusses the key features of the fractional quantum Hall effect, focusing on quasiparticles with fractional charge and statistics. It provides detailed definitions and methods for observing these properties, along with a review of current experimental status and discussions on non-Abelian statistics. The attempts to find experimental evidence for non-Abelian quasiparticles in certain quantum Hall systems are also explored.
REPORTS ON PROGRESS IN PHYSICS
(2021)
Article
Multidisciplinary Sciences
I Taktak, M. Kapfer, J. Nath, P. Roulleau, M. Acciai, J. Splettstoesser, I Farrer, D. A. Ritchie, D. C. Glattli
Summary: In this study, a novel interferometric approach was used to demonstrate that anyons maintain quantum coherence while propagating. The results have positive implications for achieving controlled quantum coherent braiding of anyons.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Miuko Tanaka, Yuya Shimazaki, Ivan Valerievich Borzenets, Kenji Watanabe, Takashi Taniguchi, Seigo Tarucha, Michihisa Yamamoto
Summary: The authors challenge the conventional wisdom and demonstrate the generation and detection of charge neutral current in a centrosymmetric material with low spin-orbit interaction. By using bilayer graphene, they observe enhanced nonlocal transport in the quantum Hall antiferromagnetic state, where spontaneous symmetry breaking occurs due to electronic correlation.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Jonathan Schirmer, C. -X. Liu, J. K. Jain
Summary: This article investigates the interplay between pairing and topological orders in a spin polarized electron system on a Hofstadter lattice. It shows that with increasing attractive interaction, the system undergoes phase transitions from a quantum Hall phase to a skyrmion lattice phase and then to a vortex phase. The experimental feasibility and observable consequences of skyrmions and Majorana modes are indicated.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Materials Science, Multidisciplinary
E. Peraticos, S. Kumar, M. Pepper, A. Siddiki, I. Farrer, D. Ritchie, G. Jones, J. Griffiths
Summary: We report experimental observations of hysteresis in the integer quantum Hall regime of a GaAs/AlGaAs heterostructure. The nonequilibrium processes arising from direct Coulomb interactions and the dissipative nature of the Hall bar, together with scattering-influenced contacts, are shown to be responsible for the observed anomalous effects. Hysteretic behavior is found for various filling factors, including both integer and fractional states.
Article
Materials Science, Multidisciplinary
Noam Schiller, Yuval Oreg, Kyrylo Snizhko
Summary: Fractional quantum Hall quasiparticles are characterized by electric charge and scaling dimension. The scaling dimension determines the anyonic statistics for simple states, while for more complex states, it helps distinguish different theoretical descriptions. A scheme for extracting the scaling dimension from tunneling noise is proposed.
Article
Optics
Wei-Lin Mu, Xiao-Xuan Li, Xiao-Qiang Shao
Summary: We propose a cooling scheme to prepare stationary entanglement of neutral atoms in the Rydberg blockade regime by the combination of periodically collective laser pumping and dissipation. This protocol aims to stabilize the system into the desired steady state independently of the initial state, without requiring coherent addressing of individual neutral atoms or fine control of Rydberg interaction intensity, thus improving the feasibility of experiments in related fields.
Article
Optics
Yang Zhao, Xiao-Feng Shi
Summary: Topological nontrivial bands can be realized via Rydberg-dressed neutral atoms. By studying a two-dimensional hard-core boson model on a honeycomb array, it is found that a fractional Chern insulator phase with Chern number C = 1/2 can exist in the system, even in the presence of weak many-body interactions.
Article
Physics, Multidisciplinary
Ke Huang, Hailong Fu, Danielle Reifsnyder Hickey, Nasim Alem, Xi Lin, Kenji Watanabe, Takashi Taniguchi, Jun Zhu
Summary: In this study, we investigate the control over valley isospin degrees of freedom in bilayer graphene using a perpendicular electric field. We observe a new even-denominator fractional quantum Hall state at filling factor v = 5/2 and the appearance of predicted daughter states and anti-Pfaffian states. These findings pave the way for manipulating valley isospin in bilayer graphene to engineer exotic topological orders and quantum information processes.
Article
Physics, Multidisciplinary
B. Friess, I. A. Dmitriev, V Umansky, L. Pfeiffer, K. West, K. von Klitzing, J. H. Smet
PHYSICAL REVIEW LETTERS
(2020)
Article
Physics, Multidisciplinary
S. I. Dorozhkin, A. A. Kapustin, V. Umansky, J. H. Smet
Article
Chemistry, Multidisciplinary
Wonjin Jang, Min-Kyun Cho, Hyeongyu Jang, Jehyun Kim, Jaemin Park, Gyeonghun Kim, Byoungwoo Kang, Hwanchul Jung, Vladimir Umansky, Dohun Kim
Summary: This study presents a high-fidelity readout method for a semiconductor hybrid qubit in GaAs double quantum dots, achieving quantum state mapping with voltage-controlled adiabatic transitions and energy-selective tunneling-based spin-to-charge conversion with a visibility of approximately 92.6%. The research also demonstrates coherent oscillations of a hybrid qubit in GaAs and explores the potential applications of this method in other materials.
Article
Multidisciplinary Sciences
Bivas Dutta, Wenmin Yang, Ron Melcer, Hemanta Kumar Kundu, Moty Heiblum, Vladimir Umansky, Yuval Oreg, Ady Stern, David Mross
Summary: Quantum Hall states have unique quantum phases characterized by gapless edge modes. The most studied nonabelian state is the spin-polarized filling factor 5/2, which can have different topological orders. By interfacing this state with another, we were able to identify its topological order as the particle-hole Pfaffian (PH-Pf) order.
Article
Physics, Applied
D. Yavorskiy, M. Szola, T. Tarkowski, J. Wrobel, P. Nowicki, V Umansky, W. Knap, J. Lusakowski
Summary: The study focuses on processing high-electron-mobility GaAs/Al0.36Ga0.64As heterostructures using electron-beam lithography and successfully achieving stimulated terahertz emission at low temperatures. The emitted photon energy is found to be smaller compared to previously reported emissions in the same category.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Multidisciplinary
Jehyun Kim, Jonginn Yun, Wonjin Jang, Hyeongyu Jang, Jaemin Park, Younguk Song, Min-Kyun Cho, Sangwoo Sim, Hanseo Sohn, Hwanchul Jung, Vladimir Umansky, Dohun Kim
Summary: In this study, we report energy-selective tunneling readout-based Hamiltonian parameter estimation of a two-electron spin qubit in a GaAs quantum dot array. By optimizing the readout fidelity, we achieved an average single-shot measurement time of 16 μs, along with adaptive initialization and efficient qubit frequency estimation based on realtime Bayesian inference. We observed a 40-fold increase in coherence time for qubit operation in a frequency heralded mode, without resorting to dynamic nuclear polarization. Additionally, we demonstrated active frequency feedback with quantum oscillation visibility, single-shot measurement fidelity, and gate fidelity of 97.7%, 99%, and 99.6%, respectively, showcasing the improvements in the overall capabilities of GaAs-based spin qubits. Pushing the sensitivity of energy-selective tunneling-based spin to charge conversion to the limit, this technique is useful for advanced quantum control protocols such as error mitigation schemes, where fast qubit parameter calibration with a high signal-to-noise ratio is crucial.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Subhradeep Misra, Michael Stern, Vladimir Umansky, Israel Bar-Joseph
Summary: This study demonstrates the characteristics and dynamics of Bose-Einstein condensation of dark excitons in GaAs coupled quantum wells at low temperatures. The results show that the condensate extends spatially beyond the optical excitation region and its density is determined by spin-flipping collisions among the excitons. The interaction between bright excitons and the condensate leads to its depletion.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Multidisciplinary
Sourav Biswas, Rajarshi Bhattacharyya, Hemanta Kumar Kundu, Ankur Das, Moty Heiblum, Vladimir Umansky, Moshe Goldstein, Yuval Gefen
Summary: The fractional charge of quasiparticles is a fundamental feature of quantum Hall effect states. At sufficiently low temperatures, the Fano factor is found to be equal to the bulk filling factor, and this noise pattern is also observed on intermediate conductance plateaux.
Article
Multidisciplinary Sciences
Bivas Dutta, Vladimir Umansky, Mitali Banerjee, Moty Heiblum
Summary: This study gapped out the integer modes by interfacing the nu = 5/2 state with integer states nu = 2 and nu = 3, and measured the thermal conductance of the isolated-interface channel. The measured half-quantized thermal conductance confirms the non-abelian nature of the nu = 5/2 state and its particle-hole Pfaffian topological order.
Article
Physics, Multidisciplinary
Ron Aharon Melcer, Sofia Konyzheva, Moty Heiblum, Vladimir Umansky
Summary: Thermal conductance measurements are crucial in condensed-matter physics for understanding topological order in two-dimensional topological insulators. A new local power measurement technique is presented to reveal the topological thermal Hall conductance, going beyond traditional two-terminal conductance measurements. This technique also proves useful in studying power carried by current fluctuations of partitioned edge modes with out-of-equilibrium distributions.
Article
Physics, Multidisciplinary
Hemanta Kumar Kundu, Sourav Biswas, Nissim Ofek, Vladimir Umansky, Moty Heiblum
Summary: In this article, the authors demonstrate the interference and braiding of anyons in a Mach-Zehnder interferometer, proving that this device is a powerful tool for probing the quantum statistics of anyonic fractional quantum Hall states.
Article
Quantum Science & Technology
Jonginn Yun, Jaemin Park, Hyeongyu Jang, Jehyun Kim, Wonjin Jang, Younguk Song, Min-Kyun Cho, Hanseo Sohn, Hwanchul Jung, Vladimir Umansky, Dohun Kim
Summary: We demonstrate the simultaneous operation and measurement of two-electron spin qubits, decoupled from nuclear noise, in a GaAs quadruple quantum dot array. Coherent Rabi oscillations of both qubits are achieved by tuning their drive frequency using real-time Hamiltonian estimators. Strong two-qubit capacitive interaction and state-conditional frequency shift are observed, consistent with theoretical predictions. The high coherence to conditional phase-flip time ratio suggests the potential for generating high-fidelity and fast quantum entanglement using a simple capacitive interaction.
NPJ QUANTUM INFORMATION
(2023)
Article
Physics, Multidisciplinary
S. Dorozhkin, A. A. Kapustin, V Umansky, J. H. Smet
Summary: The dependence of amplitudes of Shubnikov-de Haas oscillations on the magnetic field in GaAs/AlGaAs heterostructure samples irradiated with microwave radiation in the range of 130-170 GHz has been studied. Two features of radiation-induced suppression of amplitudes have been identified, with resonances appearing at the second harmonic and a more complex dependence of the second resonance on radiation frequency. Resonance absorption at the second harmonic may explain the anomalous peak in magnetoresistance observed recently.
Article
Physics, Multidisciplinary
Dongsung T. Park, Uhjin Kim, Dongkun Kim, Hwanchul Jung, Juho Choi, Cheolhee Han, Yunchul Chung, H-S Sim, V Umansky, Hyoungsoon Choi, Hyung Kook Choi
Summary: Research on mesoscopic quantum dots shows a significant energy relaxation phenomenon of hot electrons emitted, deviating from Fermi gas predictions. Simulation experiments indicated a capacitive interaction transferring energy from hot electrons to quantum dots, suggesting the presence of an overlooked relaxation mechanism intrinsic to QD emissions.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
L. Kulik, V. A. Kuznetsov, A. S. Zhuravlev, V Umansky, I. Kukushkin
PHYSICAL REVIEW RESEARCH
(2020)
