101 research outputs found
Photonic quantum information processing: A concise review
No full textPhotons have been a flagship system for studying quantum mechanics, advancing quantum information science, and developing quantum technologies. Quantum entanglement, teleportation, quantum key distribution, and early quantum computing demonstrations were pioneered in this technology because photons represent a naturally mobile and low-noise system with quantum-limited detection readily available. The quantum states of individual photons can be manipulated with very high precision using interferometry, an experimental staple that has been under continuous development since the 19th century. The complexity of photonic quantum computing devices and protocol realizations has raced ahead as both underlying technologies and theoretical schemes have continued to develop. Today, photonic quantum computing represents an exciting path to medium- and large-scale processing. It promises to put aside its reputation for requiring excessive resource overheads due to inefficient two-qubit gates. Instead, the ability to generate large numbers of photons—and the development of integrated platforms, improved sources and detectors, novel noise-tolerant theoretical approaches, and more—have solidified it as a leading contender for both quantum information processing and quantum networking. Our concise review provides a flyover of some key aspects of the field, with a focus on experiment. Apart from being a short and accessible introduction, its many references to in-depth articles and longer specialist reviews serve as a launching point for deeper study of the field.
I. INTRODUCTIONFull Tex
Experimental investigation of a multi-photon Heisenberg-limited interferometric scheme: the effect of imperfections
No full textInterferometric phase estimation is an essential tool for precise measurements of quantities such as displacement, velocity and material properties. The lower bound on measurement uncertainty achievable with classical resources is set by the shot-noise limit (SNL) that scales asymptotically as , where is the number of resources used. The experiment of [S. Daryanoosh et al., Nat. Commun. , 4606 (2018)] showed how to achieve the ultimate precision limit, the exact Heisenberg limit (HL), in ab-initio phase estimation with photon-passes, using an entangled biphoton state in combination with particular measurement techniques. The advantage of the HL over the SNL increases with the number of resources used. Here we present, and implement experimentally, a scheme for generation of the optimal triphoton state. We study experimentally and theoretically the generated state quality and its potential for phase estimation. We show that the expected usefulness of the prepared triphoton state for HL phase estimation is significantly degraded by even quite small experimental imperfections, such as optical mode mismatch and unwanted higher-order multi-photon terms in the states produced in parametric down-conversion.16 pages, 10 figures (unable to contact one of the authors; revised the author list and acknowledgement
Experimental Realization of a Quantum Autoencoder: The Compression of Qutrits via Machine Learning
No full textWith quantum resources a precious commodity, their efficient use is highly desirable. Quantum autoencoders have been proposed as a way to reduce quantum memory requirements. Generally, an autoencoder is a device that uses machine learning to compress inputs, that is, to represent the input data in a lower-dimensional space. Here, we experimentally realize a quantum autoencoder, which learns how to compress quantum data using a classical optimization routine. We demonstrate that when the inherent structure of the dataset allows lossless compression, our autoencoder reduces qutrits to qubits with low error levels. We also show that the device is able to perform with minimal prior information about the quantum data or physical system and is robust to perturbations during its optimization routine.Full Tex
Entanglement a trois
No full textFaculty of Science, Environment, Engineering and TechnologyNo Full Tex
Quantum physics: Squeeze until it hurts
No full textQuantum systems are uncertain by nature. By 'squeezing' this uncertainty, physicists can make better measurements of quantities such as distance. But overdoing it makes things burst out all over the place.Griffith Sciences, School of Natural SciencesFull Tex
Optical quantum information: The quantum information cocoon
No full textGriffith Sciences, School of Natural SciencesNo Full Tex
An experimental quantum Bernoulli factory
No full textThere has been a concerted effort to identify problems computable with quantum technology which are intractable with classical technology or require far fewer resources to compute. Recently, randomness processing in a Bernoulli factory has been identified as one such task. Here, we report two quantum photonic implementations of a Bernoulli factory, one utilising quantum coherence and single-qubit measurements and the other which uses quantum coherence and entangling measurements of two qubits. We show that the former consumes three orders of magnitude fewer resources than the best known classical method, while entanglement offers a further five-fold reduction. These concepts may provide a means for quantum enhanced-performance in the simulation of stochastic processes and sampling tasks
Advances in photonic remote entanglement sharing
No full textRemote entanglement sharing is a primitive for a range of quantum information science tasks and for fundamental studies of nonlocality. We experimentally demonstrate advances in performing secure, loss-tolerant entanglement sharing with photonic systems.Griffith Sciences, School of Natural SciencesNo Full Tex
Photonic Entanglement Sharing and Conclusively Asymmetric Nonlocality with the Detection Loophole Closed
No full text- …
