A5022157315- Quantum and electron transport phenomena
- Quantum Information and Cryptography
- Physics of Superconductivity and Magnetism
- Quantum optics and atomic interactions
- Spectroscopy and Quantum Chemical Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Quantum Computing Algorithms and Architecture
- Mechanical and Optical Resonators
- Semiconductor Quantum Structures and Devices
- Atomic and Subatomic Physics Research
- Advancements in Semiconductor Devices and Circuit Design
- Perovskite Materials and Applications
- Electronic and Structural Properties of Oxides
- Quantum Mechanics and Applications
- Surface and Thin Film Phenomena
- Graphene research and applications
- Organic Electronics and Photovoltaics
- Force Microscopy Techniques and Applications
- Molecular Junctions and Nanostructures
- Strong Light-Matter Interactions
- Luminescence Properties of Advanced Materials
- Photochemistry and Electron Transfer Studies
- Advanced Fiber Laser Technologies
RMIT University
2016-2025
ARC Centre of Excellence in Future Low-Energy Electronics Technologies
2020-2025
MIT University
2020-2025
Quantum (Australia)
2015-2024
Centre for Quantum Computation and Communication Technology
2004-2024
Australian Research Council
2021-2024
University of Chicago
2022
Chalmers University of Technology
2022
London Centre for Nanotechnology
2022
University College London
2022
Amorphous solids show surprisingly universal behaviour at low temperatures. The prevailing wisdom is that this can be explained by the existence of two-state defects within material. so-called standard tunneling model has become established framework to explain these results, yet it still leaves central question essentially unanswered-what are two-level (TLS)? This recently taken on a new urgency with rise superconducting circuits in quantum computing, circuit electrodynamics, magnetometry,...
The negatively-charged nitrogen-vacancy (NV) center in diamond is at the frontier of quantum nano-metrology and bio-sensing. Recent attention has focused on application high-sensitivity thermometry using spin resonances NV centers nano-diamond to sub-cellular biological biomedical research. Here, we report a comprehensive investigation thermal properties center's demonstrate an alternate all-optical technique that exploits temperature dependence optical Debye-Waller factor.
We describe a scheme for using an all-electrical, rapid, adiabatic population transfer between two spatially separated dots in triple-quantum dot system. The electron spends no time the middle and does not change its energy during process. Although coherent method, this may well prove useful incoherent electronic computation (for example quantum-dot cellular automata) where it provide advantage to otherwise device. It can also be thought of as limiting case type II quantum computing,...
A quantitative understanding of the dynamics biological neural networks is fundamental to gaining insight into information processing in brain. While techniques exist measure spatial or temporal properties these networks, it remains a significant challenge resolve with subcellular resolution. In this work we consider fundamentally new form wide-field imaging for neuronal based on nanoscale magnetic field sensing optically active spins diamond substrate. We analyse sensitivity system...
New magnetometry techniques based on nitrogen-vacancy (NV) defects in diamond allow for the detection of static (dc) and oscillatory (ac) nanoscopic magnetic fields, yet are limited their ability to detect fields arising from randomly fluctuating (FC) environments. We show here that FC restrict dc ac sensitivities probing NV dephasing rate a environment should permit characterization inaccessible techniques. shown be comparable those require no additional experimental overhead or sample control.
Parasitic two-level tunneling systems originating from structural material defects affect the functionality of various microfabricated devices by acting as a source noise. In particular, superconducting quantum bits may be sensitive to even single when these reside in tunnel barrier qubit's Josephson junctions, and this can exploited observe manipulate states individual systems. Here, we detect fully characterize system two strongly interacting using novel technique for high-resolution...
Interactions between quasiparticles are of fundamental importance and ultimately determine the macroscopic properties quantum matter. A famous example is phenomenon superconductivity, which arises from attractive electron-electron interactions that mediated by phonons or even other more exotic fluctuations in material. Here we introduce mobile exciton impurities into a two-dimensional electron gas investigate resulting Fermi polaron quasiparticles. We employ multi-dimensional coherent...
Quantum master equations are an invaluable tool to model the dynamics of a plethora microscopic systems, ranging from quantum optics and information processing energy charge transport, electronic nuclear spin resonance, photochemistry, more. This tutorial offers concise pedagogical introduction equations, accessible broad, cross-disciplinary audience. The reader is guided through basics with hands-on examples that increase in complexity. covers essential methods such as use Lindblad...
The use of qubits as sensitive nanoscale magnetometers has been studied theoretically and recently demonstrated experimentally. In this paper we propose a new concept, in which scanning two-state quantum system is used to probe sample through the subtle effects decoherence. Mapping both Hamiltonian decoherence properties qubit simultaneously provides unique image magnetic (or electric) field at nanoscale. resulting images are temporal well spatial variation fields created by sample. As...
In drug discovery, there is a clear and urgent need for detection of cell-membrane ion-channel operation with wide-field capability. Existing techniques are generally invasive or require specialized nanostructures. We show that quantum nanotechnology could provide solution. The nitrogen-vacancy (NV) center in nanodiamond great interest as single-atom probe nanoscale processes. However, until now nothing was known about the behavior NV complex biological environment. explore dynamics...
The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below ionization regime presence interfaces using tight-binding and band minima basis approaches compared to recent precision measurements. In contrast with previous effective mass-based results, quadratic coefficient obtained from both theories agrees closely experiments. It also shown that there significant linear effect an impurity near interface, whereas, dominates. This work represents most...
Interfacing superconducting quantum processors, working in the GHz frequency range, with optical networks and atomic qubits is a challenging task for implementation of distributed information processing as well communication. Using spin ensembles rare-earth ions provides an excellent opportunity to bridge microwave domains at level. In this Rapid Communication, we demonstrate ultralow-power, on-chip, electron-spin-resonance spectroscopy Er${}^{3+}$ spins doped Y${}_{2}$SiO${}_{5}$ crystal...
We challenge the misconception that Bloch-Redfield equations are a less powerful tool than phenomenological Lindblad for modeling exciton transport in photosynthetic complexes. This view predominantly originates from an indiscriminate use of secular approximation. provide detailed description how to model both coherent oscillations and several types noise, giving explicit examples. All issues with non-positivity overcome by consistent straightforward physical noise model. Herein also lies...
Stimulated emission is the process fundamental to laser operation, thereby producing coherent photon output. Despite negatively charged nitrogen-vacancy (NV−) centres being discussed as a potential medium since 1980s, there have been no definitive observations of stimulated from ensembles NV− date. Here we show both theoretical and experimental evidence for using light in phonon sidebands around 700 nm. Furthermore, transition photoionization stimulating wavelength reduced 620 While lasing...
Magnetic resonance detection is one of the most important tools used in life-sciences today. However, as technique detects magnetization large ensembles spins it fundamentally limited spatial resolution to mesoscopic scales. Here we detect natural fluctuations nanoscale spin at ambient temperatures by measuring decoherence rate a single quantum response introduced extrinsic target spins. In our experiments 45 nm nanodiamonds with nitrogen–vacancy (NV) were immersed solution containing 5/2...
We investigate coherent atomic tunneling of a dilute gas Bose-Einstein condensate (BEC) in three-well system. In particular, we generalize stimulated Raman adiabatic passage (STIRAP) to adiabatically transport BEC 2000 $^{7}\mathrm{Li}$ atoms between two wells with minimal occupation the intervening well. This protocol paves way for robust method control atom-optical devices.
We demonstrate a new method to directly manipulate the state of individual two-level systems (TLSs) in phase qubits. It allows one characterize coherence properties TLSs using standard microwave pulse sequences, while qubit is used only for readout. apply this measure temperature dependence TLS first time. The energy relaxation time T1 found decrease quadratically with two studied work, their dephasing measured Ramsey and spin-echo experiments be limited at all temperatures.
New magnetometry techniques based on Nitrogen Vacancy (NV) defects in diamond have received much attention of late as a means to probe nanoscale magnetic environments. The sensitivity single NV magnetometer is primarily determined by the transverse spin relaxation time, $T_2$. Current approaches improving employ crystals with high density at cost spatial resolution, or extend $T_2$ via manufacture novel isotopically pure crystals. We adopt complementary approach, which optimal dynamic...
We study a double quantum-dot system coherently coupled to an electromagnetic resonator. A current through the dot can create population inversion in levels and, within narrow resonance window, lasing state The correlates with transport properties. On one hand, this allows probing via measurement. other resulting peak resolving small differences properties (e.g., difference Zeeman splittings of two dots). For realistic situations relaxation processes have pronounced consequences. Remarkably,...
Due to interest in both solid-state-based quantum computing architectures and the application of mechanical systems nanomagnetometry, there has been considerable recent attention focused on understanding microscopic dynamics solid-state spin baths their effects coherence a controllable, coupled central electronic spin. Using systematic approach based spatial statistics spin-bath constituents, we develop detailed, purely analytic theory for central-spin decoherence problem nitrogen-vacancy...