A5036537125- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Quantum Computing Algorithms and Architecture
- Neural Networks and Reservoir Computing
- Quantum optics and atomic interactions
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Orbital Angular Momentum in Optics
- Optical Network Technologies
- Quantum and electron transport phenomena
- Mechanical and Optical Resonators
- Spectroscopy and Quantum Chemical Studies
- Advanced Thermodynamics and Statistical Mechanics
- Solid State Laser Technologies
- Advanced Frequency and Time Standards
- Cold Atom Physics and Bose-Einstein Condensates
- Laser-Matter Interactions and Applications
- Philosophy and History of Science
- Random lasers and scattering media
- Photorefractive and Nonlinear Optics
- Semiconductor Lasers and Optical Devices
- Advanced Materials Characterization Techniques
- Surface and Thin Film Phenomena
- Molecular spectroscopy and chirality
- Spectroscopy and Laser Applications
Praevium Research (United States)
2025
Griffith University
2014-2024
Centre for Quantum Computation and Communication Technology
2014-2024
Australian Research Council
2011-2021
University of Science and Technology of China
2021
CAS Key Laboratory of Urban Pollutant Conversion
2021
Quantum (Australia)
2008-2020
The University of Queensland
2003-2008
Montana State University
2001-2007
Queensland University of Technology
2003-2007
We demonstrate complete characterization of a two-qubit entangling process--a linear optics controlled-NOT gate operating with coincident detection--by quantum process tomography. use maximum-likelihood estimation to convert the experimental data into physical matrix. The matrix allows an accurate prediction operation for arbitrary input states and calculation performance measures such as average fidelity, purity, capability our gate, which are 0.90, 0.83, 0.73, respectively.
By weakly measuring the polarization of a photon between two strong measurements, we experimentally investigate correlation appearance anomalous values in quantum weak measurements and violation realism nonintrusiveness measurements. A quantitative formulation latter concept is expressed terms Leggett–Garg inequality for outcomes subsequent an individual system. We violate several measurement strengths. Furthermore, demonstrate that there one-to-one achieving strange violating inequality.
Within the hierarchy of inseparable quantum correlations, Einstein-Podolsky-Rosen steering is distinguished from both entanglement and Bell nonlocality by its asymmetry-there exist conditions where phenomenon changes being observable to not observable, simply exchanging role two measuring parties. While this one-way feature has been previously demonstrated for restricted class Gaussian measurements, general case positive-operator-valued measures even theoretical existence only recently...
Does quantum theory apply at all scales, including that of observers? New light on this fundamental question has recently been shed through a resurgence interest in the long-standing Wigner's friend paradox. This is thought experiment addressing measurement problem -- difficulty reconciling (unitary, deterministic) evolution isolated systems and (non-unitary, probabilistic) state update after measurement. Here, by building scenario with two separated but entangled friends introduced Brukner,...
We produce and holographically measure entangled qudits encoded in transverse spatial modes of single photons. With the novel use a quantum state tomography method that only requires two-state superpositions, we achieve most complete characterization qutrits to date. Ideally, provide better security than qubits bit commitment: model sensitivity this mixture show experimentally theoretically with even small amount decoherence cannot offer increased over qubits.
We experimentally determine weak values for a single photon's polarization, obtained via measurement that employs two-photon entangling operation, and postselection. The cannot be explained by semiclassical wave theory, due to the entanglement. observe variation in size of value with strength, obtaining an average S1 Stokes parameter more than order magnitude outside operator's spectrum smallest strengths.
We demonstrate phase super-resolution in the absence of entangled states. The key insight is to use inherent time-reversal symmetry quantum mechanics: our theory shows that it possible measure, as opposed prepare, Our approach robust, requiring only photons exhibit classical interference: we experimentally high-visibility with three, four, and six using a standard laser photon counters. six-photon experiment demonstrates best yet reported high visibility resolution.
We demonstrate a new architecture for an optical entangling gate that is significantly simpler than previous realizations, using partially polarizing beam splitters so only single mode-matching condition required. operation of controlled-z in both continuous-wave and pulsed regimes operation, fully characterizing it each case quantum process tomography. also resolving, nondeterministic Bell-state analyzer based on this gate. This ideally suited to guided optics implementations gates.
In a noncontextual hidden variable model of quantum theory, variables determine the outcomes every measurement in manner that is independent how implemented. Using generalization this notion to arbitrary operational theories and preparation procedures, we demonstrate particular two-party information-processing task, "parity-oblivious multiplexing," powered by contextuality sense there limit well any theory described can perform. This bound constitutes "noncontextuality inequality" violated...
Demonstrating nonclassical effects over longer and distances is essential for both quantum technology fundamental science. The main challenge loss of photons during propagation, because considering only those cases where are detected opens a "detection loophole" in security whenever parties or devices untrusted. Einstein-Podolsky-Rosen (EPR) steering equivalent to an entanglement-verification task which one party (device) We derive arbitrarily loss-tolerant tests, enabling us perform...
We present the theory of how to achieve phase measurements with minimum possible variance in ways that are readily implementable current experimental techniques. Measurements whose statistics have high-frequency fringes, such as those obtained from maximally path-entangled $(|N,0⟩+|0,N⟩)/\sqrt{2}$ (``NOON'') states, commensurately high information yield (as quantified by Fisher information). However, this is also highly ambiguous because it does not distinguish between phases at same point...
A quantum controlled-SWAP gate is demonstrated and used to implement small-scale algorithms produce high-fidelity GHZ states.
A goal of the emerging field quantum control is to develop methods for technologies function robustly in presence noise. Central issues are fundamental limitations on available information about systems and disturbance they suffer process measurement. In context a simple scenario--the stabilization non-orthogonal states qubit against dephasing--we experimentally explore use weak measurements feedback control. We find that, despite intrinsic difficultly implementing them, allow us better...
Finding exponential separation between quantum and classical information tasks is like striking gold in research. Such an advantage believed to hold for computing but proven communication complexity. Recently, a novel resource called the switch---which creates coherent superposition of causal order events, known as causality---has been harnessed theoretically new protocol providing provable separation. We experimentally demonstrate such by realizing directions two-party distributed...