A5004795643- Quantum Information and Cryptography
- Quantum Computing Algorithms and Architecture
- Quantum Mechanics and Applications
- Neural Networks and Reservoir Computing
- Quantum optics and atomic interactions
- Mechanical and Optical Resonators
- Photonic and Optical Devices
- Cold Atom Physics and Bose-Einstein Condensates
- Laser-Matter Interactions and Applications
- Advanced Thermodynamics and Statistical Mechanics
- Quantum chaos and dynamical systems
- Geophysics and Sensor Technology
- Advanced Frequency and Time Standards
- Advanced Fiber Laser Technologies
- Random lasers and scattering media
- Blockchain Technology Applications and Security
- Optical Network Technologies
- Statistical and numerical algorithms
- Optical measurement and interference techniques
- Quantum many-body systems
- Orbital Angular Momentum in Optics
- Quantum and electron transport phenomena
University of Vienna
2018-2024
Vienna Center for Quantum Science and Technology
2018-2024
FH Campus Wien
2023
Precision interferometry with quantum states has emerged as an essential tool for experimentally answering fundamental questions in physics. Optical interferometers are of particular interest because mature methods generating and manipulating light. Their increased sensitivity promises to enable tests phenomena, such entanglement, regimes where tiny gravitational effects come into play. However, this requires long decoherence-free processing which, large interferometric areas, remains...
In the macroscopic world, time is intrinsically asymmetric, flowing in a specific direction, from past to future. However, same not necessarily true for quantum systems, as some processes produce valid evolutions under reversal. Supposing that such can be probed both directions, we also consider coherent superposition of forward and backward directions. This yields broader class than ones considered so far literature, including those with indefinite causal order. this work, demonstrate an...
Single-mode optical fibers exhibit a small but non-negligible birefringence that induces random polarization rotations during light propagation. In classical interferometry these give rise to polarization-induced fading of the interferometric visibility, and in fiber-based polarimetric sensors as well quantum optics experiments, they scramble information encoded state. Correcting undesired is consequently an important part many experiments applications employing fibers. this Lab Note we...
In the past decade, toolkit of quantum information has been expanded to include processes in which basic operations do not have definite causal relations. Originally considered context unification mechanics and general relativity, these causally indefinite shown offer advantages a wide variety processing tasks, ranging from computation metrology. Here we overview experimental efforts realise them. We survey both different techniques employed, as well theoretical methods developed support...
In quantum mechanics, the unitary nature of time evolution makes it intrinsically reversible, given control over system in question. Remarkably, there have been several recent demonstrations protocols for reverting unknown unitaries scenarios where even interactions with target are unknown. These limited by their probabilistic nature, raising fundamental question whether time-reversal could be performed deterministically. Here we show that physics indeed allows this exploiting non-commuting...
One of the most striking quantum phenomena is superposition, where one particle simultaneously inhabits different states. Most methods to verify coherent superposition are indirect, in that they require distinct states be recombined. Here, we adapt an XOR game, which separated parties measure parts a superposed particle, and use it superpositions with \textit{local measurements} second independent particle. We then turn this game into resource-efficient verification scheme, obtaining...
Abstract In standard communication information is carried by particles or waves. Counterintuitively, in counterfactual and can travel opposite directions. The quantum Zeno effect allows Bob to transmit a message Alice encoding he never interacts with. A first remarkable protocol for relied on thousands of ideal optical operations high success rate performance. Experimental realizations that have thus employed post-selection demonstrate counterfactuality. This post-selection, together with...
The quantum switch is an example of a process with indefinite causal structure, and has attracted attention for its ability to outperform causally ordered computations within the circuit model. To date, realizations have made trade-off between relying on optical interferometers susceptible minute path length fluctuations limitations range fidelity implementable channels, thereby complicating their design, limiting performance, posing obstacle extending multiple parties. In this Letter, we...
Precision interferometry with quantum states has emerged as an essential tool for experimentally answering fundamental questions in physics. Optical interferometers are of particular interest due to mature methods generating and manipulating light. The increased sensitivity offered by these promises enable phenomena, such entanglement, be tested unprecedented regimes where tiny effects gravity come into play. However, this requires long decoherence-free processing which not yet been explored...
Employing an XOR game, we verify quantum superposition with local measurements only, consisting of photon-counting and coincidence detection using a second, indistinguishable photon as shared resource, without the need to re-interfere superposition.
Quantum key distribution (QKD) offers a theoretically secure method to share secret keys, yet practical implementations face challenges due noise and loss over long-distance channels. Traditional QKD protocols require extensive compensation, hindering their industrial scalability lowering the achievable rates. Alternative encode logical qubits in noise-resilient states, but at cost of using many physical qubits, increasing susceptibility limiting transmission distance. In this work, we...
Current protocols to revert time evolutions of quantum systems suffer either from low success probabilities, or not being universal - they require knowledge about the evolving state, its evolution, interaction through which evolution is reverted. We overcome these limitations, and demonstrate a novel time-reversal protocol by implementing it on photonic platform using SWITCH. The schemes universality verified clear advantage with respect optimal classical stragegy shown running large...
The quantum switch is an example of a process with indefinite causal structure, and has attracted attention for its ability to outperform causally ordered computations within the circuit model. To date, realizations have made trade-off between relying on optical interferometers susceptible minute path length fluctuations limitations range fidelity implementable channels, thereby complicating their design, limiting performance, posing obstacle extending multiple parties. In this Letter, we...
In counterfactual communication particles and information can travel in opposite directions. With our high-fidelity programmable nanophotonic processor we implement the first trace-free protocol without post-selection with a violation as low 2.4%.
In contrast to standard communication, counterfactual communication (CFC) counterintuitively allows information exchange without particle exchange. this paper we use advances in integrated photonics implement a CFC protocol that does not rely on post-selection.
As the field of artificial intelligence is pushed forward, question arises how fast autonomous machines can learn. Within intelligence, an important paradigm reinforcement learning, where agents - learning entities capable decision making interact with world they are placed in, called environment. Thanks to these interactions, receive feedback from environment and thus progressively adjust their behaviour accomplish a given goal. An in learn fulfill tasks. To answer this we consider novel...
Single-mode optical fibres exhibit a small but non-negligible birefringence that induces random polarisation rotations during light propagation. In classical interferometry these give rise to polarisation-induced fading of the interferometric visibility, and in fibre-based polarimetric sensors as well quantum optics experiments they scramble information encoded state. Correcting undesired is consequently an important part many applications employing fibres. this Lab Note we review efficient...
In standard communication information is carried by particles or waves. Counterintuitively, in counterfactual and can travel opposite directions. The quantum Zeno effect allows Bob to transmit a message Alice encoding he never interacts with. first suggested protocol not only required thousands of ideal optical components, but also resulted so-called "weak trace" the having travelled from Alice, calling scalability counterfactuality previous proposals experiments into question. Here we...
In counterfactual communication particles and information can travel in opposite directions. With our high-fidelity programmable nanophotonic processor we implement the first trace-free protocol without post-selection with a violation as low 2.4%. © 2019 The Author(s)