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Based on the measurement of quantum correlation functions, the quantum statistical properties of spectral measurements are studied for broadband radiation fields. The spectral filtering of light before its detection is compared with the…

Quantum Physics · Physics 2015-01-15 P. Grünwald , D. Vasylyev , J. Häggblad , W. Vogel

We suggest a general scheme for quantum state engineering based on conditional measurements carried out on entangled twin-beam of radiation. Realistic detection schemes such as {\sc on/off} photodetection, homodyne detection and joint…

Quantum Physics · Physics 2009-11-07 Matteo G. A. Paris , Mary Cola , Rodolfo Bonifacio

Two-color second-order correlations of the light scattered near-resonantly by a quantum dot were measured by means of spectrally-filtered coincidence detection. The effects of filter frequency and bandwidth were studied under monochromatic…

Quantum Physics · Physics 2015-05-20 M. Peiris , B. Petrak , K. Konthasinghe , Y. Yu , Z. C. Niu , A. Muller

From the nonclassicality of photon superbunching to the basic property of intensity, we characterize light with correlation and coherence functions. The correlation functions for nonstationary sources, such as short pulses, depend…

Quantum Physics · Physics 2025-04-01 Joscelyn van der Veen , Daniel F. V. James

Recent progress in the development of superconducting circuits has enabled the realization of interesting sources of nonclassical radiation at microwave frequencies. Here, we discuss field quadrature detection schemes for the experimental…

Quantum Physics · Physics 2012-09-28 C. Eichler , D. Bozyigit , A. Wallraff

We examine quantum statistics of optical photons emitted from atomic ensembles which are classically driven and simultaneously coupled to a two-level atom via microwave photon exchange. Quantum statistics and correlations are analyzed by…

Quantum Physics · Physics 2016-08-17 Ö. E. Müstecaplıoğlu

The quantum theory of electromagnetic radiation predicts characteristic statistical fluctuations for light sources as diverse as sunlight, laser radiation and molecule fluorescence. Indeed, these underlying statistical fluctuations of light…

The quantization of an optical field is a frontier in quantum optics with implications for both fundamental science and technological applications. Here, we demonstrate that a dinickel complex (Ni$_2$) traps and quantizes classical visible…

Quantum Physics · Physics 2025-04-08 Miao Meng , Ying Ning Tan , Yu Li Zhou , Zi Cong He , Zi Hao Zhong , Jia Zhou , Guang Yuan Zhu , Chun Y. Liu

Although the foundations of quantum and classical physics are much different, it is often difficult to pinpoint which features of a particular system are intrinsically "quantum". Perhapse, the most clear-cut distinction between "classical"…

Quantum Physics · Physics 2015-02-05 Piotr Szańkowski

Quantum phenomena such as entanglement can improve fundamental limits on the sensitivity of a measurement probe. In optical interferometry, a probe consisting of $N$ entangled photons provides up to a $\sqrt{N}$ enhancement in phase…

Light is known to exhibit quantum uncertainty in terms of its amplitude, phase, and polarization. However, quantum uncertainty related to coherence, which is also a fundamental physical property of light, has not been considered to date.…

With advanced micro- and nano-photonic structures, the vacuum photon-photon coupling rate is anticipated to approach the intrinsic loss rate and lead to unconventional quantum effects. Here, we investigate the classical-to-quantum…

Quantum Physics · Physics 2022-04-11 Yue-Xun Huang , Ming Li , Ke Lin , Yan-Lei Zhang , Guang-Can Guo , Chang-Ling Zou

The quasiprobability representation of quantum states addresses two main concerns, the identification of nonclassical features and the decomposition of the density operator. While the former aspect is a main focus of current research, the…

Quantum Physics · Physics 2018-10-26 J. Sperling , I. A. Walmsley

We present a non-perturbative method through which local probes can access the two-point function of a quantum field within a region of spacetime. By considering a lattice of gapless particle detectors, we identified the probe observables…

Quantum Physics · Physics 2026-05-20 Sebastian Holmén , T. Rick Perche

We consider the problem of the measurement of very small displacements in the transverse plane of an optical image with a split photodetector. We show that the standard quantum limit for such a measurement, which is equal to the diffraction…

Optics · Physics 2009-11-13 Claude Fabre , J. -B. Fouet , Agnès Maître

We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance (NMR) setup and employing geometric discord, we evaluate the quantum correlations of a…

Entanglement is an extraordinary feature of quantum mechanics. Sources of entangled optical photons were essential to test the foundations of quantum physics through violations of Bell's inequalities. More recently, entangled many-body…

Extracting meaningful information about unknown quantum states without performing a full tomography is an important task. Low-dimensional projections and random measurements can provide such insight but typically require careful crafting.…

Photon-pair correlations in spontaneous parametric down conversion are ubiquitous in quantum photonics. The ability to engineer their properties for optimising a specific task is essential, but often challenging in practice. We demonstrate…

Quantum Physics · Physics 2024-03-11 Chloé Vernière , Hugo Defienne

We show with explicit formulas that one can completely identify an unknown quantum process with only one weakly entangled state; and identify a quantum optical Gaussian process with either one two-mode squeezed state or a few different…

Quantum Physics · Physics 2010-10-05 Xiang-Bin Wang , J. -Z. Hu , Z. -W. Yu , Franco Nori