A5031571726- Quantum Computing Algorithms and Architecture
- Quantum Information and Cryptography
- Quantum and electron transport phenomena
- Quantum Mechanics and Applications
- Quantum-Dot Cellular Automata
- Advancements in Semiconductor Devices and Circuit Design
- Quantum many-body systems
- Advanced Thermodynamics and Statistical Mechanics
- Force Microscopy Techniques and Applications
- Neural Networks and Reservoir Computing
- Parallel Computing and Optimization Techniques
- Diamond and Carbon-based Materials Research
- Atomic and Subatomic Physics Research
- Advanced Electron Microscopy Techniques and Applications
- High-pressure geophysics and materials
- Electronic Packaging and Soldering Technologies
- Computational Physics and Python Applications
- Advanced Fluorescence Microscopy Techniques
- Semiconductor materials and devices
- Tensor decomposition and applications
- Computability, Logic, AI Algorithms
- Mechanical stress and fatigue analysis
- Quantum optics and atomic interactions
- Machine Learning and ELM
- Laser-Matter Interactions and Applications
Centre for Quantum Computation and Communication Technology
2012-2025
The University of Melbourne
2016-2025
UNSW Sydney
2023-2025
Intel (United States)
2005-2018
Quantum (Australia)
2004-2010
University of Liverpool
2006-2008
The University of Queensland
2003-2007
BT Group (United Kingdom)
1989
John Innes Centre
1969
The exceptionally long quantum coherence times of phosphorus donor nuclear spin qubits in silicon, coupled with the proven scalability silicon-based nano-electronics, make them attractive candidates for large-scale computing. However, high threshold topological error correction can only be captured a two-dimensional array operating synchronously and parallel-posing formidable fabrication control challenges. We present an architecture that addresses these problems through novel shared-control...
Characterisation protocols have so far played a central role in the development of noisy intermediate-scale quantum (NISQ) computers capable impressive feats. This trajectory is expected to continue building next generation devices: ones that can surpass classical for particular tasks -- but progress characterisation must keep up with complexities intricate device noise. A missing piece zoo procedures tomography which completely describe non-Markovian dynamics over given time frame. Here, we...
Quantum communication typically involves a linear chain of repeater stations, each capable reliable local quantum computation and connected to their nearest neighbors by unreliable links. The rate existing protocols is low as two-way classical used. By using surface code across the generating Bell pairs between neighboring stations with probability heralded success greater than 0.65 fidelity 0.96, we show that can be avoided information sent over arbitrary distances arbitrarily error at...
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.
Abstract The ability to prepare sizeable multi-qubit entangled states with full qubit control is a critical milestone for physical platforms upon which quantum computers are built. We investigate the extent entanglement found within prepared graph state on 20-qubit superconducting computer IBM Q Poughkeepsie . along path consisting of all twenty qubits device and performed tomography groups four connected this path. determined that each pair was inseparable hence entangled. Additionally,...
Abstract The ability to generate large‐scale entanglement is an important progenitor of quantum information processing capability in noisy intermediate‐scale (NISQ) devices. In this paper, the extent which entangled states over large numbers qubits can be prepared on current superconducting devices investigated. Native‐graph IBM Quantum 65‐qubit ibmq_manhattan device and 53‐qubit ibmq_rochester are readout‐error mitigation (QREM) applied. Connected graphs spanning each full detected,...
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...
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...
Substitutional donor atoms in silicon are promising qubits for quantum computation with extremely long relaxation and dephasing times demonstrated. One of the critical challenges scaling these systems is determining inter-donor distances to achieve controllable wavefunction overlap while at same time performing high fidelity spin readout on each qubit. Here we such a device by means scanning tunnelling microscopy lithography. We measure anti-correlated states between two donor-based...
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...
Recent breakthrough demonstrations of the measurement and control a single atom's electrons nuclear spins in silicon have added momentum to pursuit quantum computing. New results show that two-qubit logic gates can perform with high fidelity, without need for placing atoms subnanometer precision.
Abstract Quantum computers have the potential to speed up certain computational tasks. A possibility this opens within field of machine learning is use quantum techniques that may be inefficient simulate classically but could provide superior performance in some Machine algorithms are ubiquitous particle physics and as advances made technology there a similar adoption these techniques. In work support vector (QSVM) implemented for signal-background classification. We investigate effect...
The efficient preparation of quantum states is an important step in the execution many algorithms. In noisy intermediate-scale (NISQ) computing era, this a significant challenge given resources are scarce and typically only low-depth circuits can be implemented on physical devices. We present genetic algorithm for state (GASP) which generates relatively initialising computer specified state. method uses basis set [Formula: see text], CNOT gates to systematically generate synthesize target...
Spin qubits in silicon are strong contenders for the realization of a practical quantum computer. Single- and two-qubit gates have shown fidelities above fault-tolerant threshold, entanglement three has been achieved. Furthermore, high-fidelity operation algorithms is possible. Here we implement four-qubit processor with all control threshold. We demonstrate three-qubit Grover's search algorithm ~95% probability finding marked state. To this end, fabricate from phosphorus atoms...
Multi-time quantum processes are endowed with the same richness as multipartite states, including temporal entanglement and exotic causal structures. However, experimentally probing these rich phenomena leans heavily on fast clean mid-circuit measurements, which rarely available. We show here how surprisingly accessible in nascent processors even when faced substantially limited control. work within limitation where only unitary control is allowed, followed by a terminating measurement....
We propose a scheme for quantum information processing based on donor electron spins in semiconductors, with an architecture complementary to the original Kane proposal. show that naive implementation of spin qubits provides only modest improvement over scheme, however through introduction global gate control we are able take full advantage fast evolution timescales. estimate latent clock speed is 100-1000 times nuclear computer ratio $T_{2}/T_{ops}$ approaching $10^{6}$ level.
In this paper we propose a superadiabatic protocol where quantum state transfer can be achieved with arbitrarily high accuracy and minimal control across long spin chains an odd number of spins. The only requires the couplings between qubits on edge chain. We predict fidelities above 0.99 for evolution nanoseconds using typical spin-exchange coupling values $\ensuremath{\mu}\mathrm{eV}$. Furthermore, by building formalism top protocol, effective that retains over chain further improves fidelity.
There are many cases where the interaction between two qubits is not precisely known, but single qubit operations available. In this paper we show how, regardless of an incomplete knowledge strength or form qubits, it often possible to construct a CNOT gate which has arbitrarily high fidelity. particular, that oscillations in exchange solid state Si and Ge structures correctable.
Recent work on fault-tolerant quantum computation making use of topological error correction shows great potential, with the 2d surface code possessing a threshold rate approaching 1\%. However, requires complex state distillation procedure to achieve universal computation. The color is related scheme partially solving problem, providing means perform all Clifford group gates transversally. We review and its correcting methodology, discussing one approximate technique based graph matching....
Abstract Imaging the atomic structure of a single biomolecule is an important challenge in physical biosciences. Whilst existing techniques all rely on averaging over large ensembles molecules, single-molecule realm remains unsolved. Here we present protocol for 3D magnetic resonance imaging molecule using quantum spin probe acting simultaneously as sensor and source field gradient. Signals corresponding to specific regions molecule’s nuclear density are encoded state probe, which used...
Abstract Quantum computers hold promise to circumvent the limitations of conventional computing for difficult molecular problems. However, accumulation quantum logic errors on real devices represents a major challenge, particularly in pursuit chemical accuracy requiring inclusion electronic correlation effects. In this work we implement computed moments (QCM) approach hydrogen chain systems up H $$_6$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow...
From an open system perspective non-Markovian effects due to a nearby bath or neighboring qubits are dynamically equivalent. However, there is conceptual distinction account for: may be controlled. We combine recent advances in quantum process tomography with the framework of classical shadows characterize spatiotemporal correlations. Observables here constitute operations applied system, where free operation maximally depolarizing channel. Using this as causal break, we systematically erase...
As quantum technology advances and the size of computers grow, it becomes increasingly important to understand extent quality in devices. large-scale entanglement is a resource crucial for achieving advantage, challenge its generation makes valuable benchmark measuring performance universal In this paper, we study Greenberger-Horne-Zeilinger (GHZ) graph states prepared on range IBM Quantum We generate GHZ investigate their coherence times with respect state dynamical decoupling techniques. A...