A5053412639- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Graphene research and applications
- Advancements in Semiconductor Devices and Circuit Design
- Quantum Computing Algorithms and Architecture
- Surface and Thin Film Phenomena
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Quantum Information and Cryptography
- Quantum many-body systems
- Semiconductor Quantum Structures and Devices
- Integrated Circuits and Semiconductor Failure Analysis
- 2D Materials and Applications
- Ion-surface interactions and analysis
- Quantum chaos and dynamical systems
- Advanced Semiconductor Detectors and Materials
- Spectroscopy and Quantum Chemical Studies
- Rare-earth and actinide compounds
- Theoretical and Computational Physics
- Mechanical and Optical Resonators
- Diamond and Carbon-based Materials Research
- Electron and X-Ray Spectroscopy Techniques
- Superconductivity in MgB2 and Alloys
- Magnetic Field Sensors Techniques
UNSW Sydney
2017-2024
Centre for Quantum Computation and Communication Technology
2017-2024
University of Technology Sydney
2024
Stadtwerke Jülich (Germany)
2022
Delft University of Technology
2012-2017
QuTech
2017
Majorana fermions are particles identical to their own antiparticles. They have been theoretically predicted exist in topological superconductors. We report electrical measurements on InSb nanowires contacted with one normal (Au) and superconducting electrode (NbTiN). Gate voltages vary electron density define a tunnel barrier between contacts. In the presence of magnetic fields order 100 mT we observe bound, mid-gap states at zero bias voltage. These bound remain fixed even when gate...
Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They offered an exceptional testbed for superconductivity, leading the realization of hybrid systems combining macroscopic properties superconductors with possibility control charges down a single electron. These advances brought semiconductor forefront efforts realize topological superconductivity Majorana modes. A prime challenge benefit from...
Topological superconductivity is a state of matter that can host Majorana modes, the building blocks topological quantum computer. Many experimental platforms predicted to show such rely on proximity-induced superconductivity. However, accessing properties requires an induced hard superconducting gap, which challenging achieve for most material systems. We have systematically studied how interface between InSb semiconductor nanowire and NbTiN superconductor affects properties. Step by step,...
Abstract Efficient scaling and flexible control are key aspects of useful quantum computing hardware. Spins in semiconductors combine information processing with electrons, holes or nuclei, electric magnetic fields, scalable coupling via exchange dipole interaction. However, accessing large Hilbert space dimensions has remained challenging, due to the short-distance nature interactions. Here, we present an atom-based semiconductor platform where a 16-dimensional is built by combined...
Junctions created by coupling two superconductors via a semiconductor nanowire in the presence of high magnetic fields are basis for potential detection, fusion, and braiding Majorana bound states. We study $\mathrm{NbTiN}/\mathrm{InSb}$ $\text{nanowire}/\mathrm{NbTiN}$ Josephson junctions find that dependence critical current on field exhibits gate-tunable nodes. This is contrast with well-known Fraunhofer effect, under which nodes form regular pattern period fixed junction area. Based...
Abstract Silicon chips containing arrays of single dopant atoms can be the material choice for classical and quantum devices that exploit donor spins. For example, group‐V donors implanted in isotopically purified 28 Si crystals are attractive large‐scale computers. Useful attributes include long nuclear electron spin lifetimes 31 P, hyperfine clock transitions 209 Bi or electrically controllable 123 Sb Promising architectures require ability to fabricate individual near‐surface with high...
In 2021 Nature Physics published a paper by Vaitiekenas, Liu, Krogstrup and Marcus titled "Zero-bias peaks at zero magnetic field in ferromagnetic hybrid nanowires". The reports low temperature transport measurements on semiconductor InAs nanowires with two partly overlapping shells -- shell of EuS, insulator, Al, metal that becomes superconducting temperatures below 1.2K. claims (1) the data are consistent induced topological superconductivity Majorana modes (MZMs), (2) this is facilitated...
We present recommendations for how to improve reproducibility in the field of condensed matter physics. This area physics has consistently produced both fundamental insights into functioning as well transformative inventions. Our result from a collaboration that includes researchers academia and government laboratories, scientific journalists, legal professionals, representatives publishers, professional societies, other experts. The group met person May 2024 at conference University...
Out-of-time-ordered correlation functions (OTOCs) play a crucial role in the study of thermalization, entanglement, and quantum chaos, as they quantify scrambling information due to complex interactions. As consequence their out-of-time-ordered nature, OTOCs are difficult measure experimentally. Here we propose an OTOC measurement protocol that does not rely on reversal time evolution is easy implement range experimental settings. The accounts for both pure mixed initial states, applicable...
Most classical dynamical systems are chaotic. The trajectories of two identical prepared in infinitesimally different initial conditions diverge exponentially with time. Quantum systems, instead, exhibit quasiperiodicity due to their discrete spectrum. Nonetheless, the dynamics quantum whose counterparts chaotic expected show some features that resemble motion. Among many controversial aspects quantum-classical boundary, emergence chaos remains among least experimentally verified....
Abstract Semiconductor spin qubits combine excellent quantum performance with the prospect of manufacturing devices using industry‐standard metal‐oxide‐semiconductor (MOS) processes. This applies also to ion‐implanted donor spins, which further afford exceptional coherence times and large Hilbert space dimension in their nuclear spin. Here multiple strategies are demonstrated integrated manufacture scale‐up donor‐based computers. 31 PF 2 molecule implants used triple placement certainty...
Already a building block of modern life, silicon is also poised to power the next leap in information technology, which quantum mechanical properties single impurities located just beneath its surface can be used create vastly more powerful computers. Here multinational team presents specialized microscope better understand inner workings such chips, by scanning finely focused beam ultralow-energy ions across surface. The tiny ``click'' that each ion makes when it hits chip detected and...
We present a scalable strategy to manufacture quantum computer devices, by encoding information in the combined electron-nuclear spin state of individual ion-implanted phosphorus dopant atoms silicon. Our allows typical pitch between bits order 200 nm, and retains compatibility with standard fabrication processes adopted classical CMOS nanoelectronic devices. theoretically predict fast high-fidelity logic operations, preliminary experimental progress towards realization "flip-flop" qubit system.
Efficient scaling and flexible control are key aspects of useful quantum computing hardware. Spins in semiconductors combine information processing with electrons, holes or nuclei, electric magnetic fields, scalable coupling via exchange dipole interaction. However, accessing large Hilbert space dimensions has remained challenging, due to the short-distance nature interactions. Here, we present an atom-based semiconductor platform where a 16-dimensional is built by combined electron-nuclear...
Abstract Semiconductor spin qubits combine excellent quantum performance with the prospect of manufacturing devices using industry-standard metal-oxide-semiconductor (MOS) processes. This applies also to ion-implanted donor spins, which further afford exceptional coherence times and large Hilbert space dimension in their nuclear spin. Here we demonstrate integrate multiple strategies manufacture scale-up donor-based computers. We use 31 PF 2 molecule implants triple placement certainty...
This work re-analyzes Gul et al. Nature Nanotechnology 2018 "Ballistic Majorana nanowire devices" using fuller data from the original experiments released in 2023 on Zenodo. The authors have prepared a correction to their article that appeared 2024. However, does not address concerns we identify here. We demonstrate contain extensive evidence for quantum dots and disorder are completely inconsistent with authors' conclusion they achieved ballistic devices containing zero bias peaks of likely...
Out-of-time-ordered correlation functions (OTOCs) play a crucial role in the study of thermalization, entanglement, and quantum chaos, as they quantify scrambling information due to complex interactions. As consequence their out-of-time-ordered nature, OTOCs are difficult measure experimentally. Here we propose an OTOC measurement protocol that does not rely on reversal time evolution is easy implement range experimental settings. The accounts for both pure mixed initial states, applicable...
The attributes of group-V-donor spins implanted in an isotopically purified $^{28}$Si crystal make them attractive qubits for large-scale quantum computer devices. Important features include long nuclear and electron spin lifetimes $^{31}$P, hyperfine clock transitions $^{209}$Bi electrically controllable $^{123}$Sb spins. However, architectures scalable devices require the ability to fabricate deterministic arrays individual donor atoms, placed with sufficient precision enable high-fidelity...
Near-Surface Doping In article number 2103235, David N. Jamieson and co-workers report that single-crystal silicon can be configured with arrays of single, near-surface, dopant atoms using on-chip electrodes low-noise charge-sensitive electronics to register single-ion implants. Suitable for integration a nanostencil scanner localize the implants, system makes use signal electron–hole pairs generated as ions dissipate their kinetic energy in crystal. The part an engineering strategy...
The development of devices that exhibit both superconducting and semiconducting properties is an important endeavor for emerging quantum technologies. We investigate nanowires fabricated on a silicon-on-insulator (SOI) platform. Aluminum from deposited contact electrodes found to interdiffuse with Si along the entire length nanowire, over micrometer scales at temperatures well below Al–Si eutectic. phase-transformed material conformal predefined device patterns. transformed mesoscopic ring...