A5019238779- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Quantum Computing Algorithms and Architecture
- Neural Networks and Reservoir Computing
- Quantum optics and atomic interactions
- Orbital Angular Momentum in Optics
- Laser-Matter Interactions and Applications
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Advanced Optical Sensing Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Random lasers and scattering media
- Mechanical and Optical Resonators
- Advanced Battery Technologies Research
- Sparse and Compressive Sensing Techniques
- Semiconductor Lasers and Optical Devices
- Electric Vehicles and Infrastructure
- Advanced Thermodynamics and Statistical Mechanics
- Law, Economics, and Judicial Systems
- Optical measurement and interference techniques
- Advanced Fiber Laser Technologies
- Quantum-Dot Cellular Automata
- Optical Network Technologies
- Laser-Plasma Interactions and Diagnostics
Universidade de São Paulo
2023-2025
The University of Queensland
2011-2024
ARC Centre of Excellence for Engineered Quantum Systems
2011-2024
Australian Research Council
2012-2022
Quantum (Australia)
2007-2022
Centre for Quantum Computation and Communication Technology
2010-2017
Queensland University of Technology
2007-2014
Universidade Federal do Rio de Janeiro
2001-2008
We demonstrate the difference between local, single-particle dynamics and global of entangled quantum systems coupled to independent environments. Using an all-optical experimental setup, we showed that, even when environment-induced decay each system is asymptotic, entanglement may suddenly disappear. This “sudden death” constitutes yet another distinct counterintuitive trait entanglement.
Deterministic quantum computation with one pure qubit (DQC1) is an efficient model of that uses highly mixed states. Unlike pure-state models, its power not derived from the generation a large amount entanglement. Instead it has been proposed other nonclassical correlations are responsible for computational speedup, and these can be captured by discord. In this Letter we implement DQC1 in all-optical architecture, experimentally observe generated correlations. We find no entanglement, but...
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.
Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of through the violation a inequality considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices cheat by hiding unfavourable events losses. Here we close this "detection loophole" combining highly efficient source...
A boson-sampling device is a quantum machine expected to perform tasks intractable for classical computer, yet requiring minimal nonclassical resources as compared full-scale computers. Photonic implementations date employed sources based on inefficient processes that only simulate heralded single-photon statistics when strongly reducing emission probabilities. Boson sampling with input has thus never been realized. Here, we report operated bright solid-state source of Fock states high...
We report on an experimental investigation of the dynamics entanglement between a single qubit and its environment, as well for pairs qubits interacting independently with individual environments, using photons obtained from parametric down-conversion. The are encoded in polarizations photons, while interaction environment is implemented by coupling polarization each photon momentum. A convenient Sagnac interferometer allows implementation several decoherence channels continuous monitoring...
We present a proof of principle demonstration quantum key distribution scheme in higher-order -dimensional alphabets using spatial degrees freedom photons. Our implementation allows for the transmission 4.56 bits per sifted photon, while providing improved security: an intercept-resend attack on all photons would induce average error rate 0.47. Using our system, it should be possible to send more than byte information photon.
The resources required to characterise the dynamics of engineered quantum systems-such as computers and sensors-grow exponentially with system size. Here we adapt techniques from compressive sensing reduce experimental configurations for process tomography. Our method is applicable dynamical processes that are known be nearly-sparse in a certain basis it can implemented using only single-body preparations measurements. We perform efficient, high-fidelity estimation matrices on an experiment...
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...
The desiderata for an ideal photon source are high brightness, single-photon purity, and indistinguishability. Defining brightness at the first collection lens, these properties have been simultaneously demonstrated with solid-state sources, however absolute efficiencies remain close to 1% level, indistinguishability only photons emitted consecutively on few nanosecond scale. Here we employ deterministic quantum dot-micropillar devices demonstrate sources scalable performance. In one device,...
Superconducting transition-edge sensors (TES) are extremely sensitive microcalorimeters used as photon detectors with unparalleled energy resolution. They have found application from measuring astronomical spectra through to determining the quantum property of photon-number, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow class="MJX-TeXAtom-ORD"><mml:mover><mml:mi>n</mml:mi><mml:mo stretchy="false">&#x005E;</mml:mo></mml:mover></mml:mrow><mml:mrow...
The key requirement for quantum networking is the distribution of entanglement between nodes. Surprisingly, can be generated across a network without direct transfer---or communication---of entanglement. In contrast to information gain, which cannot exceed communicated information, gain bounded by discord, more general measure correlation that includes but not limited Here, we experimentally entangle two communicating parties sharing three initially separable photonic qubits exchange carrier...
We present a simple technique to reduce the emission rate of higher-order photon events from pulsed spontaneous parametric down-conversion. The uses extra-cavity control over mode locked ultrafast laser simultaneously increase repetition and energy each pulse pump beam. apply our scheme photonic quantum gate, showing improvements in non-classical interference visibility for 2-photon 4-photon experiments, quantum-gate fidelity entangled state production case.
We demonstrate unambiguous entangling operation of a photonic quantum-logic gate driven by an ultrabright solid-state single-photon source. Indistinguishable single photons emitted semiconductor quantum dot in micropillar optical cavity are used as target and control qubits. For source brightness 0.56 collected photons-per-pulse, the measured truth table has overlap with ideal case 68.4%, increasing to 73.0% for 0.17 photons- per-pulse. The is entangling: at 0.48, Bell-state fidelity above...
Transmission flexibility is a key component of current power systems and demands reconfiguration alternatives to expand transmission infrastructure. This paper addresses the use Battery Energy Storage System (BESS) as an asset system that provides increased capacity. Furthermore, BESS also supports operational procedures in course re-establishment normal operation during transients, which helps maintain quality requirements. A case study presented assess additional capabilities 30 MW/60 MWh...
We report on an experiment demonstrating the conservation of orbital angular momentum in stimulated down-conversion. It has been demonstrated that is not transferred to individual beams spontaneous also known it conserved when twin photons are taken individually. observe law for beam down-conversion through cavity-free emission.
Tests such as Bell's inequality and Hardy's paradox show that joint probabilities correlations between distant particles in quantum mechanics are inconsistent with local realistic theories. Here we experimentally demonstrate these concepts the time domain, using a photonic entangling gate to perform nondestructive measurements on single photon at different times. We is much stronger violation of temporal Bell independent state, including for fully mixed states.
Abstract A scheme for active temporal‐to‐spatial demultiplexing of single photons generated by a solid‐state source is introduced. The scales quasi‐polynomially with photon number, providing viable technological path routing n in the one temporal stream from emitter to different spatial modes. Active demonstrated using state‐of‐the‐art source—a quantum‐dot deterministically coupled micropillar cavity—and custom‐built demultiplexer—a network electro‐optically reconfigurable waveguides...
We investigate the estimation of a small interaction parameter from outcomes weak quantum measurements implemented by interaction. The relation values and sensitivity is explained different contributions postselected results are identified using experimental data. show how can be used to control distribution input state between outcomes.
We investigate the utility of Einstein-Podolsky-Rosen correlations position and momentum photon pairs from parametric down-conversion in implementation a secure quantum key distribution protocol. show that security is guaranteed by entanglement between downconverted pairs, can be checked either direct comparison Alice Bob's measurement results or evaluation an inequality sort proposed Mancini et al. (Phys. Rev. Lett. 88, 120401 (2002)).
Not all quantum protocols require entanglement to outperform their classical alternatives. The nonclassical correlations that lead a advantage are conjectured be captured by discord. Here we demonstrate discord has an immediate practical application: it allows client who lacks the ability generate or conduct measurements certify whether untrusted party entangling gates. We implement our protocol in discrete-variable regime with photonic qubits and show its success presence of high levels...
Measuring entanglement is a demanding task that usually requires full tomography of quantum system, involving number observables grows exponentially with the parties. Recently, it was suggested adding single ancillary qubit would allow for efficient measurement concurrence, and indeed any monotone associated antilinear operations. Here, we report on experimental implementation such device---an embedding simulator---in photonics, encoding entangling dynamics bipartite system into tripartite...