Article
Optics
P. Neveu, J. Delpy, S. Liu, C. Banerjee, J. Lugani, F. Bretenaker, E. Brion, F. Goldfarb
Summary: A study demonstrated the generation of squeezed vacuum states of light using four wave mixing at room temperature, working at resonance with an atomic transition. Investigation into the properties of these states showed that the noise variances of the squeezed and anti-squeezed quadratures cannot be explained solely by losses. A theoretical model incorporating residual absorption and spontaneous emission provided an excellent agreement with experimental data without any adjusted parameter.
Article
Optics
Hugo Kerdoncuff, Jesper B. Christensen, Mikael Lassen
Summary: This study presents experimental results on quantum frequency conversion for producing non-classical light and achieving squeezing effects. Limitations in practical applications were identified, requiring further development for potential use in various fields.
Article
Optics
Biveen Shajilal, Oliver Thearle, Aaron Tranter, Yuerui Lu, Elanor Huntington, Syed Assad, Ping Koy Lam, Jiri Janousek
Summary: This paper presents a bow-tie optical parametric amplifier (OPA) for generating squeezed vacuum states, which exhibits high squeezing levels and long-term stability. It has potential applications in various quantum fields.
Article
Physics, Multidisciplinary
Jacob Hastrup, Kimin Park, Radim Filip, Ulrik Lund Andersen
Summary: A method is proposed for generating highly squeezed vacuum states with low excess antisqueezing using a few oscillator-qubit coupling gates through a Rabi-type interaction Hamiltonian, which can be implemented with different methods and is compatible with other protocols manipulating quantum harmonic oscillators.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Marco Malitesta, Augusto Smerzi, Luca Pezze
Summary: We propose an entangled distributed quantum sensing scheme based on a group of Mach-Zehnder interferometers (MZIs) for the estimation of relative phase shifts. The scheme overcomes shot-noise limit and achieves improved sensitivity using an optimization analysis. The entangled strategy reduces resource overhead and can achieve higher gain.
Article
Optics
Hiroko Tomoda, Takato Yoshida, Takahiro Kashiwazaki, Takeshi Umeki, Yutaro Enomoto, Shuntaro Takeda
Summary: One of the leading approaches to large-scale quantum information processing is the continuous-variable scheme based on time multiplexing. Conventional CV TM experiments have used fixed light sources that can only output squeezed pulses with the same squeezing levels and phases. However, we demonstrate a programmable time-multiplexed squeezed light source that can generate sequential squeezed pulses with various squeezing levels and phases at a time interval below 100 ns. This light source enables arbitrary generation patterns through software, without changing its hardware configuration. It is expected to implement various large-scale CV QIP tasks.
Article
Physics, Applied
Hector M. Moya-Cessa, Felipe A. Asenjo, Sergio A. Hojman, Francisco Soto-Eguibar
Summary: In this paper, we demonstrate how two-mode squeezed vacuum-like states can be engineered using the Bohm-Madelung formalism by choosing the phase of the wave function. The difference between our wave function and the traditional squeezed vacuum states lies in the precise phase we selected. This engineering approach is made possible by the existence of the Bohm potential, and it holds potential for various applications in the propagation of optical fields.
MODERN PHYSICS LETTERS B
(2022)
Article
Physics, Multidisciplinary
Joscha Heinze, Benno Willke, Henning Vahlbruch
Summary: Mirror thermal noise is a main limitation for future ground-based gravitational-wave detectors, with the proposal of using higher-order spatial laser modes to mitigate this noise further. Current detectors reduce quantum noise by injecting squeezed vacuum states, while operating in higher-order modes would require efficient generation of squeezed vacuum states in these modes. A significant milestone has been achieved in generating continuous-wave squeezed states in higher-order modes, paving the way for their usage in future gravitational-wave detectors and other quantum noise limited experiments.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Christian Drago, Agata M. Branczyk
Summary: In this paper, a method for generating tunable squeezed vacuum states of light with multiple modes encoded in frequency bins is proposed. The method utilizes custom-engineered spontaneous parametric down-conversion driven by a pulse-shaped pump field to generate multimode squeezed states, which can be tuned in real time by adjusting the properties of the pump field. Exploring new quantum states of light encoded in new degrees of freedom can be a fruitful path towards discovering new quantum applications.
Article
Optics
Dongmei Han, Na Wang, Meihong Wang, Zhongzhong Qin, Xiaolong Su
Summary: In this study, we experimentally demonstrate the remote preparation and manipulation of squeezed light, verifying the effectiveness of the entanglement-based model and indicating potential applications in remote quantum information processing.
Article
Physics, Mathematical
Tamirat Abebe, Demissie Jobir, Chimdessa Gashu, Ebisa Mosisa
Summary: This paper thoroughly analyzes the quantum properties of a two-level atom interacting with a squeezed vacuum reservoir. It is found that the width of the power spectrum of light increases with the squeeze parameter, r, and in the absence of decay constant and interaction time, it enhances the probability for the atom to be in the upper level.
ADVANCES IN MATHEMATICAL PHYSICS
(2021)
Article
Physics, Multidisciplinary
Stephan Grebien, Julian Goettsch, Boris Hage, Jaromir Fiurasek, Roman Schnabel
Summary: In this experiment, the multistep distillation of squeezed states was analyzed for the first time. By utilizing probabilistic subtraction and Gaussification, the squeeze factor was successfully increased, surpassing the limitations set by the pumped medium's effective nonlinearity.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Jun Li, Chengjie Zhu, Yaping Yang
Summary: In this study, we propose the generation of squeezed light accompanied by hyperradiance through quantum interference in a linear system consisting of a high-quality optical cavity and two coherently driven two-level qubits. The results demonstrate that squeezed light can be generated in the hyperradiance regime under the conditions of strong coupling and weak driving, and the orthogonal angles of the squeezed light can be controlled by adjusting the frequency detuning between the driving field and the qubits.
Article
Quantum Science & Technology
Jascha Zander, Roman Schnabel
Summary: The study discusses an optical ensemble measurement setup that can monitor the time-dependent change of a quantum state's displacement in phase space with precision 10 dB below the Heisenberg uncertainty limit. This achievement supports the potential of quantum technology in entanglement-enhanced metrology, sensing, and measurement-based quantum computing.
NPJ QUANTUM INFORMATION
(2021)
Article
Optics
Huan Zhang, Wei Ye, Chaoping Wei, Ying Xia, Shoukang Chang, Zeyang Liao, Liyun Hu
Summary: The study focuses on using multiphoton catalysis two-mode squeezed vacuum state to enhance the phase sensitivity of interferometers. Results show that this state exhibits stronger nonclassical characteristics and is more sensitive to photon losses, especially in scenarios of serious photon losses and small initial squeezing. The findings have important implications in quantum metrology.
Article
Optics
Rayssa B. de Andrade, Hugo Kerdoncuff, Kirstine Berg-Sorensen, Tobias Gehring, Mikael Lassen, Ulrik L. Andersen
Article
Physics, Multidisciplinary
S. T. Pradyumna, E. Losero, I. Ruo-Berchera, P. Traina, M. Zucco, C. S. Jacobsen, U. L. Andersen, I. P. Degiovanni, M. Genovese, T. Gehring
COMMUNICATIONS PHYSICS
(2020)
Article
Multidisciplinary Sciences
Tobias Gehring, Cosmo Lupo, Arne Kordts, Dino Solar Nikolic, Nitin Jain, Tobias Rydberg, Thomas B. Pedersen, Stefano Pirandola, Ulrik L. Andersen
Summary: The article discusses the experimental implementation of a quantum random number generator using homodyne measurements, providing a security proof that considers quantum side-information. Security analysis takes into account Gaussianity and stationarity of noise processes, as well as correlations between consecutive measurement outcomes due to finite detection bandwidth. The experimental realization demonstrates a real-time generation rate of 2.9 Gbit/s.
NATURE COMMUNICATIONS
(2021)
Article
Quantum Science & Technology
Hou-Man Chin, Nitin Jain, Darko Zibar, Ulrik L. Andersen, Tobias Gehring
Summary: The implementation of a machine learning framework, specifically an unscented Kalman filter (UKF), for phase noise estimation in CV-QKD systems can effectively control excess noise. Experimental results show that the UKF can ensure very low excess noise even at low pilot powers, with low variance and high stability across a wide range of pilot signal to noise ratios. This may lead to CV-QKD systems with low hardware complexity and versatility for different transmission lines.
NPJ QUANTUM INFORMATION
(2021)
Article
Quantum Science & Technology
Stefano Pirandola, Carlo Ottaviani, Christian S. Jacobsen, Gaetana Spedalieri, Samuel L. Braunstein, Tobias Gehring, Ulrik L. Andersen
Summary: The study explores the application of a quantum relay in quantum communication protocols, showing that classical correlations in the environment can reactivate entanglement distribution protocols by guaranteeing the distribution of a weaker form of entanglement. Additionally, experimental evidence demonstrates that memory effects in the environment can significantly enhance the performance of a quantum relay beyond established limits for quantum and private communications.
NPJ QUANTUM INFORMATION
(2021)
Article
Quantum Science & Technology
Nitin Jain, Ivan Derkach, Hou-Man Chin, Radim Filip, Ulrik L. Andersen, Vladyslav C. Usenko, Tobias Gehring
Summary: This study identified a modulation leakage vulnerability in continuous-variable quantum key distribution systems, caused by inadequate suppression of certain sidebands during modulation. The leakage was found to impact the range of secret key obtainment and could potentially lead to security breaches, with additional trusted noise proving effective in countering this vulnerability.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Multidisciplinary Sciences
Nitin Jain, Hou-Man Chin, Hossein Mani, Cosmo Lupo, Dino Solar Nikolic, Arne Kordts, Stefano Pirandola, Thomas Brochmann Pedersen, Matthias Kolb, Bernhard Omer, Christoph Pacher, Tobias Gehring, Ulrik L. Andersen
Summary: This paper introduces a continuous-variable quantum key distribution (CVQKD) protocol that can generate composable keys secure against collective attacks. By using Gaussian-modulated coherent states and improving the security proof and system operation, this CVQKD protocol overcomes the difficulty of key generation in existing protocols. This advance brings CVQKD implementations closer to their discrete-variable counterparts in terms of practicality, performance, and security.
NATURE COMMUNICATIONS
(2022)
Article
Quantum Science & Technology
Hou-Man Chin, Nitin Jain, Ulrik L. Andersen, Darko Zibar, Tobias Gehring
Summary: Continuous variable quantum key distribution (CV-QKD) is a promising emerging technology for secure key distribution. We propose a digital synchronization procedure that is independent of modulation format and does not require hardware modifications. Experimental results show its performance in CV-QKD systems.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Quantum Science & Technology
I Suleiman, J. A. H. Nielsen, X. Guo, N. Jain, J. Neergaard-Nielsen, T. Gehring, U. L. Andersen
Summary: In this research, we demonstrate the generation, transmission, and detection of single-mode squeezed states of light at 1550 nm using real-time phase control. The system achieves significant noise suppression with standard telecom-compatible components. The compactness and simplicity of the implemented scheme make it a relevant candidate for long distance quantum communication in future photonic quantum networks.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Quantum Science & Technology
Adnan A. E. Hajomer, Nitin Jain, Hossein Mani, Hou-Man Chin, Ulrik L. Andersen, Tobias Gehring
Summary: This study proposes a CVQKD system without modulation leakage vulnerability, achieving state preparation and measurement using baseband modulation and an IQ modulator. The system can generate a composable secret key secure against collective attacks.
NPJ QUANTUM INFORMATION
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Nitin Jain, Hou-Man Chin, Hossein Mani, Erik Bidstrup, Ulrik L. Andersen, Tobias Gehring
Summary: Continuous-variable quantum cryptography utilizes existing telecommunication technology for secure key distribution, and qTReX is a low-noise, highly stable, semi-autonomous prototype using optical coherent states.
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Iyad Suleiman, Jens Arnbak, Xueshi Guo, Jonas Neergaard-Nielsen, Tobias Gehring, Ulrik Lund Andersen
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Renato R. Domeneguetti, Hauke Conradi, Moritz Kleinert, Christian Kiesler, Michael Stefszky, Harald Herrmann, Christine Silberhorn, Ulrik L. Andersen, Jonas Schou Neergaard-Nielsen, Tobias Gehring
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Article
Optics
Hossein Mani, Tobias Gehring, Philipp Grabenweger, Bernhard Omer, Christoph Pacher, Ulrik Lund Andersen
Summary: Continuous-variable quantum key distribution uses coherent states of light to distribute encryption keys, with efficient information reconciliation being essential. Low channel coding rate error-correcting codes, such as MET-LDPC codes, are crucial for achieving highly efficient reconciliation at low rates.
Proceedings Paper
Engineering, Electrical & Electronic
D. Zibar, U. C. Moura, H. M. Chin, A. M. Rosa Brusin, N. Jain, F. Da Ros, S. Kleis, C. Schaeffer, T. Gehring, U. L. Andersen, A. Carena
2020 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC)
(2020)