A conclusive experiment to throw more light on "light"

We describe a new realization of Ghose, Home, Agarwal experiment on wave particle duality of light where some limitations of the former experiment, realized by Mizobuchi and Ohtake, are overcome. Our results clearly indicate that wave-particle complementarity must be understood between interference and "whelcher weg" knowledge and not in a more general sense

Bell measurements as a witness of a dualism in entanglement

We show how a property of dualism, which can exist in the entanglement of identical particles, can be tested in the usual photonic Bell measurement apparatus with minor modifications. Two different sets of coincidence measurements on the same experimental setup consisting of a Hong-Ou-Mandel interferometer demonstrate how the same two-photon state can emerge entanglement in the polarization or the momentum degree of freedom depending on the dynamical variables used for labeling the particles. Our experiment demonstrates how the same source can be used as both a polarization entangled state, as well as a dichotomic momentum entangled state shared between distant users Alice and Bob in accordance to which sets of detectors they access. When the particles become distinguishable by letting the information about one of the variables to be imprinted in yet another (possibly inaccessible) system or degree of freedom, the feature of dualism is expected to vanish. We verify this feature by polarization decoherence (polarization information in environment) or arrival time difference, which both respectively destroy one of the dual forms of entanglement.Comment: 5 pages, 4 figure

The time as an emergent property of quantum mechanics, a synthetic description of a first experimental approach

The "problem of time" in present physics substantially consists in the fact that a straightforward quantization of the general relativistic evolution equation and constraints generates for the Universe wave function the Wheeler-De Witt equation, which describes a static Universe. Page and Wootters considered the fact that there exist states of a system composed by entangled subsystems that are stationary, but one can interpret the component subsystems as evolving: this leads them to suppose that the global state of the universe can be envisaged as one of this static entangled state, whereas the state of the subsystems can evolve. Here we synthetically present an experiment, based on PDC polarization entangled photons, that allows showing with a practical example a situation where this idea works, i.e. a subsystem of an entangled state works as a "clock" of another subsystem

On the reconstruction of diagonal elements of density matrix of quantum optical states by on/off detectors

We discuss a scheme for reconstructing experimentally the diagonal elements of the density matrix of quantum optical states. Applications to PDC heralded photons, multi-thermal and attenuated coherent states are illustrated and discussed in some details.Comment: 10 pages, presented at Palermo "TQMFA2005" Conference. To appear on "Open Systems & Information Dynamics" (2006

Exploring Quantum Correlations from Discord to Entanglement

Quantum correlations represent a fundamental tool for studies ranging from basic science to quantum technologies. Different non-classical correlations have been identified and studied, as entanglement and discord. In this Paper we explore experimentally the rich geometry of polarization Bell-diagonal states. By taking advantage of the statistical method of generation, the values of entanglement and discord along different trajectories in the space of the parameters of density matrix have been measured. The effects of sudden death of entanglement and complete "freeze" of discord were investigated in order to detect the domains with different domination of one type of quantum correlation against to other. A geometric interpretation for each considered phenomena is addressed. The observed good agreement between experiment and theory for all investigated trajectories ensures the reliability of this method

Quantum state reconstruction using binary data from on/off photodetection

The knowledge of the density matrix of a quantum state plays a fundamental role in several fields ranging from quantum information processing to experiments on foundations of quantum mechanics and quantum optics. Recently, a method has been suggested and implemented in order to obtain the reconstruction of the diagonal elements of the density matrix exploiting the information achievable with realistic on/off detectors, e.g. silicon avalanche photo-diodes, only able to discriminate the presence or the absence of light. The purpose of this paper is to provide an overview of the theoretical and experimental developments of the on/off method, including its extension to the reconstruction of the whole density matrix.Comment: revised version, 11 pages, 6 figures, to appear as a review paper on Adv. Science Let

Self consistent, absolute calibration technique for photon number resolving detectors

Well characterized photon number resolving detectors are a requirement for many applications ranging from quantum information and quantum metrology to the foundations of quantum mechanics. This prompts the necessity for reliable calibration techniques at the single photon level. In this paper we propose an innovative absolute calibration technique for photon number resolving detectors, using a pulsed heralded photon source based on parametric down conversion. The technique, being absolute, does not require reference standards and is independent upon the performances of the heralding detector. The method provides the results of quantum efficiency for the heralded detector as a function of detected photon numbers. Furthermore, we prove its validity by performing the calibration of a Transition Edge Sensor based detector, a real photon number resolving detector that has recently demonstrated its effectiveness in various quantum information protocols.Comment: 9 pages, 2 figure

Quantum and classical characterization of single/few photon detectors

This paper's purpose is to review the results recently obtained in the Quantum Optics labs of the National Institute of Metrological Research (INRIM) in the field of single- and few-photon detectors calibration, from both the classical and quantum viewpoint. In the first part of the paper is presented the calibration of a single-photon detector with absolute methods, while in the second part we focus on photon-number-resolving detectors, discussing both the classical and quantum characterization of such devices.Comment: Quantum Matter in pres

Psychological impact and health-related quality-of-life outcomes of Mayer-Rokitansky-Küster-Hauser syndrome : A systematic review and narrative synthesis

Mayer-Rokitansky-K\ufcster-Hauser syndrome causes absence or underdevelopment of uterus and vagina, but women's subjective experience remains understudied. This systematic review was conducted to examine the psychological and health-related quality-of-life outcomes of Mayer-Rokitansky-K\ufcster-Hauser syndrome. In total, 22 articles identified through electronic search matched the inclusion criteria and were included in our review. Mayer-Rokitansky-K\ufcster-Hauser syndrome may be associated with psychological symptoms and impaired quality of life, but especially with poor sexual esteem and genital image. Women may experience difficulties managing intimacy and disclosing to partners. Mothers may be perceived as overinvolved, with consequent negative emotions in women with the disease