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We investigate quantum phase estimation in a Mach-Zehnder interferometer using q-deformed photon states, including q-coherent and q-cat states, which model realistic deviations from ideal light sources. By deriving closed-form photon count…

Quantum Physics · Physics 2025-10-07 Duttatreya , Sanjib Dey

Interferometry with quantum light is known to provide enhanced precision for estimating a single phase. However, depending on the parameters involved, the quantum limit for the simultaneous estimation of multiple parameters may not…

Quantum Physics · Physics 2014-03-07 Philip J. D. Crowley , Animesh Datta , Marco Barbieri , Ian A. Walmsley

The quantum statistical fluctuations of the electromagnetic field establish a limit, known as the shot-noise limit, on the sensitivity of optical measurements performed with classical technologies. However, quantum technologies are not…

We propose and analyze a multi-functional setup consisting of high finesse optical cavities, beam splitters, and phase shifters. The basic scheme projects arbitrary photonic two-mode input states onto the subspace spanned by the product of…

Quantum Physics · Physics 2015-03-13 Anne E. B. Nielsen , Christine A. Muschik , Geza Giedke , K. G. H. Vollbrecht

Single photons provide excellent quantum information carriers, but current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed single photons, while…

Quantum Physics · Physics 2012-02-07 N. K. Langford , S. Ramelow , R. Prevedel , W. J. Munro , G. J. Milburn , A. Zeilinger

Based on correlations of coherently displaced photon-numbers, we derive entanglement criteria for the purpose to verify non-Gaussian entanglement. Our construction method enables us to verify bipartite and multipartite entanglement of…

Quantum Physics · Physics 2017-09-08 B. Kühn , W. Vogel , J. Sperling

Gaussian boson sampling exploits squeezed states to provide a highly efficient way to demonstrate quantum computational advantage. We perform experiments with 50 input single-mode squeezed states with high indistinguishability and squeezing…

In this paper we investigate whether it is in general possible to substitute maximally path-entangled states, namely NOON-states by classical light in a Doppleron-type resonant multiphoton detection processes by studying adaptive phase…

Quantum Physics · Physics 2015-06-12 Sabine Wölk , Wenchao Ge , M. Suhail Zubairy

Quantum metrology research promises approaches to build new sensors that achieve the ultimate level of precision measurement and perform fundamentally better than modern sensors. Practical schemes that tolerate realistic fabrication…

Interferometric phase measurement is widely used to precisely determine quantities such as length, speed, and material properties. Without quantum correlations, the best phase sensitivity $\Delta\varphi$ achievable using $n$ photons is the…

We address potential deviations of radiation field from the bosonic behaviour and employ local quantum estimation theory to evaluate the ultimate bounds to precision in the estimation of these deviations using quantum-limited measurements…

Quantum Physics · Physics 2014-07-09 Giovanni De Cillis , Matteo G. A. Paris

Two-photon processes are crucial in applications like microscopy and microfabrication, but their low cross-section requires intense illumination and limits, e.g., the penetration depth in nonlinear microscopy. Entangled states have been…

Quantum computer, harnessing quantum superposition to boost a parallel computational power, promises to outperform its classical counterparts and offer an exponentially increased scaling. The term "quantum advantage" was proposed to mark…

We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the…

Quantum Physics · Physics 2010-07-20 Hugo Cable , Gabriel A. Durkin

We present an in-depth analysis regarding the error resistance and optimization of our all-optical Bell measurement and ultrafast long-distance quantum communication scheme proposed in [arXiv:1503.06777]. In order to promote our previous…

Quantum Physics · Physics 2017-02-01 Fabian Ewert , Peter van Loock

We derive a bound on the precision of state estimation for finite dimensional quantum systems and prove its attainability in the generic case where the spectrum is non-degenerate. Our results hold under an assumption called local asymptotic…

Quantum Physics · Physics 2019-05-09 Yuxiang Yang , Giulio Chiribella , Masahito Hayashi

To acquire the best path-entangled photon Fock states for robust quantum optical metrology with parity detection, we calculate phase information from a lossy interferometer by using twin entangled Fock states. We show that (a) when loss is…

Quantum Physics · Physics 2013-05-30 Kebei Jiang , Chase J. Brignac , Yi Weng , Moochan B. Kim , Hwang Lee , Jonathan P. Dowling

Quantum computing using two optical coherent states as qubit basis states has been suggested as an interesting alternative to single photon optical quantum computing with lower physical resource overheads. These proposals have been…

Quantum Physics · Physics 2009-11-13 A. P. Lund , T. C. Ralph , H. L. Haselgrove

We propose novel coherent-state phase concentration by probabilistic measurement-induced ampli- fication. The amplification scheme uses novel architecture, thermal noise addition (instead of single photon addition) followed by feasible…

Quantum Physics · Physics 2015-05-13 Petr Marek , Radim Filip

Loss is a critical roadblock to achieving photonic quantum-enhanced technologies. We explore a modular platform for implementing integrated photonics experiments and consider the effects of loss at different stages of these experiments,…