Esben Bork Hansen
A5031066292- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Advanced Condensed Matter Physics
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Quantum Structures and Devices
- Graphene research and applications
- Low-power high-performance VLSI design
- Quantum many-body systems
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Advanced Semiconductor Detectors and Materials
- Microwave and Dielectric Measurement Techniques
- Physics of Superconductivity and Magnetism
- Sensor Technology and Measurement Systems
- Advanced Electrical Measurement Techniques
- Electron Spin Resonance Studies
- Magnetic properties of thin films
- Lubricants and Their Additives
- Surface and Thin Film Phenomena
- Terahertz technology and applications
- Photonic and Optical Devices
- Cold Atom Physics and Bose-Einstein Condensates
- Algebraic structures and combinatorial models
- Adhesion, Friction, and Surface Interactions
- Characterization and Applications of Magnetic Nanoparticles
Microsoft (United States)
2023-2025
University of Copenhagen
1971-2018
Ørsted (Denmark)
1989-1997
Danish Academy of Technical Sciences
1988
Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, control of Majorana bound states (MBSs). We demonstrate emergence MBSs from coalescing Andreev (ABSs) in a hybrid InAs nanowire with epitaxial Al, using quantum dot at end as spectrometer. Electrostatic gating tuned density to regime one or few ABSs. In an applied axial magnetic field, topological phase emerges which ABSs move zero energy remain there, forming MBSs. observed...
Topological phases of matter can enable highly stable qubits with small footprints, fast gate times, and digital control. These hardware-protected must be fabricated a material combination in which topological phase reliably induced. The challenge: disorder destroy the obscure its detection. This paper reports on devices low enough to pass gap protocol, thereby demonstrating gapped superconductivity paving way for new qubit.
We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e gate voltage, consistent transport through an excited (poisoned) state island. Comparison simple model yields estimate parity lifetime for strongly coupled (∼1 μs) and sets bound weakly (>10 μs). Fluctuations gate-voltage spacing peaks at high field, reflecting hybridization, are...
Two-terminal conductance spectroscopy of superconducting devices is a common tool for probing Andreev and Majorana bound states. Here, we study theoretically three-terminal setup, with two normal leads coupled to grounded terminal. Using single-electron scattering matrix, derive the subgap matrix discuss its symmetries. In particular, show that local nonlocal elements have pairwise identical antisymmetric components. Moreover, find are directly related BCS charges states close probes how...
We describe a concrete device roadmap towards fault-tolerant quantum computing architecture based on noise-resilient, topologically protected Majorana-based qubits. Our encompasses four generations of devices: single-qubit that enables measurement-based qubit benchmarking protocol; two-qubit uses braiding to perform Clifford operations; an eight-qubit can be used show improvement operation when performed logical qubits rather than directly physical qubits; and topological array supporting...
We present measurements of one-dimensional superconductor-semiconductor Coulomb islands, fabricated by gate confinement a two-dimensional InAs heterostructure with an epitaxial Al layer. When tuned via electrostatic side gates to regimes without subgap states, blockade reveals Cooper-pair mediated transport. states are present, peak positions and heights oscillate in correlated way magnetic field voltage, as predicted theoretically, (anti)crossings (parallel) transverse indicating...
A pulsed, nanosecond fibre laser with wavelength of 1064 nm was used to texture grade 316 stainless steel and 'low alloy' carbon in order generate contacts high static friction coefficients. High have applications reducing the tightening force required joints or easily secure precision fittings, particularly for larger components where standard methods are difficult expensive. Friction tests performed at normal pressures 100 MPa 50 shown that very coefficients greater than 1.25, an increase...
Recent tunneling spectroscopy experiments in semiconducting nanowires with proximity-induced superconductivity have reported robust zero-bias conductance peaks. Such a feature can be compatible the existence of topological Majorana bound states (MBSs) and trivial Andreev state (ABS) near zero energy. Here, we argue that additional information, distinguish between two cases, extracted from Coulomb blockade islands. The key is ratio peak heights consecutive peaks gives information about...
Recent experimental searches for signatures of Majorana-type excitations in proximitized semiconducting nanowires involve conductance spectroscopy, where the evidence sought after is a robust zero-bias peak (in longer wires) and its characteristic field-dependent splitting shorter wires). Although results partially confirm theoretical predictions, commonly observed discrepancies still include (i) that significantly lower than predicted value $2{e}^{2}/h$ (ii) absence expected ``Majorana...
We theoretically study the differential conductance of a one-dimensional normal-superconductor-normal-superconductor (N-SNS) junction with phase bias applied between two superconductors. consider specifically formed by spin-orbit coupled semiconducting nanowire regions having superconducting pairing induced bulk $s$-wave superconductor. When is tuned into topologically nontrivial Zeeman field, it hosts zero-energy Majorana modes at its ends as well interface The phase-dependent splitting...
We present measurements and simulations of semiconductor-superconductor heterostructure devices that are consistent with the observation topological superconductivity Majorana zero modes. The fabricated from high-mobility two-dimensional electron gases in which quasi-one-dimensional wires defined by electrostatic gates. These enable local non-local transport properties have been optimized via extensive to ensure robustness against non-uniformity disorder. Our main result is several devices,...
The fusion of non-Abelian anyons or topological defects is a fundamental operation in measurement-only quantum computation. In superconductors, this amounts to determination the shared fermion parity Majorana zero modes. As step towards this, we implement single-shot interferometric measurement indium arsenide-aluminum heterostructures with gate-defined nanowire. interferometer formed by tunnel-coupling proximitized nanowire dots. causes state-dependent shift these dots' capacitance up 1 fF....
In this article we study measurement circuit effects in three-terminal electrical transport measurements arising from finite line impedances. We provide exact expressions relating the measured voltages and differential conductances to their values at device under test, which allow for spurious voltage divider be corrected. Finally, test implementation of these corrections with experimental measurements.
Laughlin's fractionally charged quasi-holes and quasi-electrons are assumed to be pinned, subject a force j* Phi 0 from the transport current. A balance argument then explains existence of Hall plateaus.
It is shown that there a regime below the critical current, Ic, for breakdown, where longitudinal Hall resistivity grows essentially exponentially with transport current. According to present theory this subcritical behavior determines value of Ic.
In a mid-plateau situation there exists reversible uphill flow (in the direction of Hall field Ey) electron liquid with current density Jliq.. Inelastic processes cause excitations to be scattered downhill Jexc., which satisfies condition Jexc. + Jliq. = 0. The conversion at edge dissipative is mediated by states. It shown that transverse circulation electrons implies temperature independence ratio Δρxy/ρxxmin, where ρxxmin minimal value longitudinal resistivity given T, and Δρxy ρxy(T) − ρxy(0).