A5013420170- Quantum and electron transport phenomena
- Quantum many-body systems
- Physics of Superconductivity and Magnetism
- Topological Materials and Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Surface and Thin Film Phenomena
- Graphene research and applications
- Quantum Computing Algorithms and Architecture
- Black Holes and Theoretical Physics
- Quantum, superfluid, helium dynamics
- Quantum Information and Cryptography
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Stochastic processes and statistical mechanics
- Noncommutative and Quantum Gravity Theories
- Theoretical and Computational Physics
- Electronic and Structural Properties of Oxides
- Research Data Management Practices
- Quantum-Dot Cellular Automata
- Superconductivity in MgB2 and Alloys
- Magnetic Field Sensors Techniques
- Advanced NMR Techniques and Applications
- Scientific Computing and Data Management
- Quantum optics and atomic interactions
- Advancements in Semiconductor Devices and Circuit Design
ETH Zurich
2015-2023
Princeton University
2019-2021
A key challenge in fabrication of superconductor (S)-semiconductor (Sm) hybrid devices is forming highly transparent contacts between the active electrons semiconductor and superconducting metal. In this work, we show that a near perfect interface contact can be achieved using epitaxial growth aluminum on an InAs two-dimensional electron system. We demonstrate material system, Al-InAs, satisfies all requirements necessary to reach into topological regime by individual characterization...
We present a class of Hamiltonians $H$ for which sector the Hilbert space invariant under Lie group $G$, is not symmetry $H$, possesses essential properties many-body scar states. These include absence thermalization and "revivals" special initial states in time evolution. Some found earlier work may be viewed as cases our construction. A particular examples concerns interacting spin-1/2 fermions on lattice consisting $N$ sites (it includes deformations Fermi-Hubbard model cases), we show...
It has been shown [K. Pakrouski et al., Phys. Rev. Lett. 125, 230602 (2020)] that three families of highly symmetric states are many-body scars for any spin-$\frac{1}{2}$ fermionic Hamiltonian the form ${H}_{0}+OT$, where $T$ is a generator an appropriate Lie group. One these consists well-known $\ensuremath{\eta}$-pairing states. In addition to having usual properties scars, insensitive electromagnetic noise and have advantages storing processing quantum information. this paper we show...
Quantized resistance---the fractional quantum Hall effect---was used to uncover the mysterious so-called 5/2 state. Theoretical modeling suggests that spin-polarized electrons in GaAs semiconductors defining this state host a fundamentally new type of particle.
Transport measurements are performed on InAs/GaSb double quantum wells at zero and finite magnetic fields applied parallel perpendicular to the wells. We investigate a sample in inverted regime where electrons holes coexist, compare it with another noninverted semiconducting regime. The activated behavior conjunction strong suppression of resistance peak charge neutrality point field attest topological hybridization gap between electron hole bands sample. observe an unconventional Landau...
We numerically study the fractional quantum Hall effect at filling factors $\nu=12/5$ and 13/5 (the particle-hole conjugate of 12/5) in high-quality two-dimensional GaAs heterostructures via exact diagonalization including finite well width Landau level mixing. find that mixing suppresses $\nu=13/5$ relative to $\nu=12/5$. By contrast, we both $\nu=2/5$ (its conjugate) $\nu=3/5$ effects lowest be robust under well-width corrections. Our results provide a possible explanation for experimental...
In some quantum many-body systems, the Hilbert space breaks up into a large ergodic sector and much smaller scar subspace. It has been suggested [K. Pakrouski et al., Phys. Rev. Lett. 125, 230602 (2020)] that two sectors may be distinguished by their transformation properties under group whose rank grows with system size (it is not symmetry of Hamiltonian). The scars are invariant this group, while all other states not. Here we apply idea to lattice systems containing $M$ Majorana fermions...
After decades since its discovery, a complete understanding of the topological phase matter at $\frac{5}{2}$ filling appears to be lacking. Previous numerical studies have narrowed candidates Moore-Read Pfaffian or anti-Pfaffian. Recent thermal transport measurements point another variant, particle-hole Pfaffian, which has nonholomorphic pairing part that complicates comparison with other competing states. Here, authors constructed exact holomorphic wave function full symmetry and compared energetics
We study the quantum mechanics of three-index Majorana fermions ψ^{abc} governed by a quartic Hamiltonian with O(N)^{3} symmetry. Similarly to Sachdev-Ye-Kitaev model, this tensor model has solvable large-N limit dominated melonic diagrams. For N=4 total number states is 2^{32}, but they naturally break up into distinct sectors according charges under U(1)×U(1) Cartan subgroup one O(4) groups. The biggest sector vanishing and contains over 165 million states. Using Lanczos algorithm, we...
Stability of quantum many-body scars in spin-1/2 fermionic systems under typical perturbations is investigated, revealing insights for experimental detection and theoretical computing applications.
We formulate an optimization problem of Hamiltonian design based on the variational principle. Given a ansatz for we construct loss function to be minimised as weighted sum relevant properties specifying thereby search query. Using fractional quantum Hall effect test system illustrate how framework can used determine generating finite-size model wavefunction (Moore-Read Pfaffian and Read-Rezayi states), find optimal conditions experiment or "extrapolate" given wavefunctions in certain...
We discuss two types of quantum mechanical models that couple large numbers Majorana fermions and have orthogonal symmetry groups. In vector type, only one the groups has a rank. The $N$ limit is taken keeping $gN=\ensuremath{\lambda}$ fixed, where $g$ multiplies quartic Hamiltonian. introduce simple model with $O(N)\ifmmode\times\else\texttimes\fi{}SO(4)$ symmetry, whose energies are expressed in terms quadratic Casimirs This may be deformed so...
We present two 2-body Hamiltonians that approximate the exact PH-Pfaffian wavefunction with their ground states for all system sizes where this has been numerically constructed to date. The wavefunctions have high overlap original and reproduce well low-lying entanglement spectrum structure factor. generating are obtained by an optimisation procedure three four pseudopotentials varied in neighbourhood of second Landau level Coulomb interaction or a non-interacting model. They belong finite...
In this paper we present a simple, yet typical simulation in statistical physics, consisting of large scale Monte Carlo simulations followed by an involved analysis the results. The purpose is to provide example publication explore tools for writing reproducible papers. estimates critical temperature where Ising model on square lattice becomes magnetic be Tc /J = 2.26934(6) using finite size scaling crossing points Binder cumulants. We virtual machine which can used reproduce all figures and
We provide a method for constructing many-body scar states in fermionic lattice models that incorporate given type of correlations with one the maximizing them over full Hilbert space. Therefore this state may always be made ground by adding such as "pairing potential" $\delta H_0$ to any Hamiltonian $H=H_0+OT$ supporting group-invariant scars [arXiv:2007.00845]. In case single-flavour spin-full fermions is special BCS wavefunction written real space and invariant under site index...
In some quantum many-body systems, the Hilbert space breaks up into a large ergodic sector and much smaller scar subspace. It has been suggested [arXiv:2007.00845] that two sectors may be distinguished by their transformation properties under group whose rank grows with system size (it is not symmetry of Hamiltonian). The scars are invariant this group, while all other states not. Here we apply idea to lattice systems containing $M$ Majorana fermions per site. for $N$ sites decomposed action...
We study the stability of many-body scars in spin-1/2 fermionic systems under most typical perturbations relevant materials. find that some families are completely insensitive to certain perturbations. In other cases they stable first order perturbation theory. Our analytical results apply a large class Hamiltonians known [arXiv:2106.10300] support exact scars. For numerical calculations we choose deformed $t-J-U$ model includes both Heisenberg and Hubbard interactions. propose two new...