True photon-counting devices in the optical may open a new observationnal window in astrophysics: photon statistics and quamtum properties of light. We rapidly develop below the scientific context and the mathematical basis to understand photon statistics. We discuss the relevance of microquasars in our galaxy as a strong scientific case for a possible photon-counting instrument.
True photon-counting devices in the optical may open a new observationnal window in astrophysics: photon statistics and quamtum properties of light. We rapidly develop below the scientific context and the mathematical basis to understand photon statistics. We discuss the relevance of microquasars in our galaxy as a strong scientific case for a possible photon-counting instrument.
The entire optical astronomy relies upon the detection of light. In this contribution, we put emphasis to the fact that a new window to the universe could be opened with the obvious idea of applying the …Quantum Theory to describe incoming light Quanta (!). It is clearly the appropriate approach but, nevertheless, it never deemed necessary in main stream astrophysics: Customarily, traditional astronomy not only prefers time‐averaged quantities, (although fluctuations in time of a measurement can be a source of information which is getting entirely lost in any time‐averaged value) but misses much more information content by continuing to use old semi‐classical approaches to treat photon detection processes. Thus, we fail to describe and appreciate in full very important properties of cosmic light, like spatiotemporal coherence. Nevertheless, 45 years of knowledge accumulation in Quantum Optics and technology can now result to the development of instruments capable to extract intimate quantum information scrambled in the incoming optical light fields from celestial sources, provided their ability to detect light emission alterations in the <ns timescales, can be demonstrated. In the emerging field of Quantum or “Photonic” Astrophysics (QAp) random fluctuations of light are not considered undesirable as unavoidable photon‐noise that hampers the photometrical precision, but, instead, as a subject of investigation per se. Such light fluctuations can frequently be valuable as a rich source of information. Statistical fluctuations, are able to provide radically new diagnostic methods of physical conditions in astrophysical plasmas by directly identifying characteristic quantum signatures of light‐generating or light‐scattering processes. However, it has to be noted that, close enough to the quantum limit, the bosonic character of photon cannot be ignored and, therefore, a detailed Quantum Electrodynamical treatment of the interaction of the incoming photon stream with every component comprising the chain of physical systems from the source to the detecting instrument, has to be elaborated. To propagate the main ideas regarding the framework of QAp is not an easy task. Here, summarize the conceptual foundations and experimental aspects of such a new information channel and then describe the main strategy aspects, to develop the subject. We discuss also, briefly, the scientific rationale, prospects and difficulties of the above mentioned instruments and describe the aims of our key‐program to contribute in their realization.
Why the Quantum of Quasars Workshop? Or more precisely: why reopening the questions of second-order photon correlations in astrophysics? The answer lies in the combination of three things. First, quantum optics made fantastic progresses since the original experiment by Hanbury Brown & Twiss; progresses ignored so far in astrophysics. Second, the astrophysics community plans to built giant telescopes and telescope arrays. Third, there have been important technological breakthroughs in the field of ultra-fast low-light detectors. More importantly, light carries much more information that its instantaneous frequency, intensity and polarization. For a scientific field aiming at exploring the Universe, and whose exploration tools are mostly based on light, it is stunning to realize that so far, astrophysics mostly remained at the first order of photon correlations, and furthermore extremely exciting to explore the possible links or applications of quantum light studies in astrophysics. The slides of all talks are available at http://quantumofquasars.org.
Why the Quantum of Quasars Workshop?Or more precisely: why reopening the questions of second-order photon correlations in astrophysics?The answer lies in the combination of three things.First, quantum optics made fantastic progresses since the original experiment by Hanbury Brown & Twiss; progresses ignored so far in astrophysics.Second, the astrophysics community plans to built giant telescopes and telescope arrays.Third, there have been important technological breakthroughs in the field of ultra-fast low-light detectors.More importantly, light carries much more information that its instantaneous frequency, intensity and polarization.For a scientific field aiming at exploring the Universe, and whose exploration tools are mostly based on light, it is stunning to realize that so far, astrophysics mostly remained at the first order of photon correlations, and furthermore extremely exciting to explore the possible links or applications of quantum light studies in astrophysics.The slides of all talks are available at http://quantumofquasars.org.
Abstract Quantum optics potentially offers an information channel from the Uni-verse beyond the established ones of imaging and spectroscopy. All existing cam-eras and all spectrometers measure aspects of the first-order spatial and/or temporal coherence of light. However, light has additional degrees of freedom, manifest in the statistics of photon arrival times, or in the amount of photon orbital angular mo-mentum. Such quantum-optical measures may carry information on how the light was created at the source, and whether it reached the observer directly or via some intermediate process. Astronomical quantum optics may help to clarify emission processes in natural laser sources and in the environments of compact objects, while high-speed photon-counting with digital signal handling enables multi-element and long-baseline versions of the intensity interferometer. Time resolutions of nanosec-onds are required, as are large photon fluxes, making photonic astronomy very timely in an era of large telescopes. 1 What Is Observed in Astronomy? Almost all of astronomy depends on the interpretation of properties of electromag-netic radiation (“light”) from celestial sources. The sole exceptions are neutrino detections; gravitational-wave searches; analyses of cosmic rays, meteorites, and other extraterrestrial materials; and in-situ studies of solar-system bodies. All our other understanding of the Universe rests upon observing and interpreting more or less subtle properties in the light reaching us from celestial bodies. Astronomical telescopes are equipped with myriads of auxiliary instruments which, on first sight, may give an impression of being vastly different. However, a closer examination of the underlying physical principles reveals that they all are measuring either the spatial or temporal [first-order] coherence of light (or perhaps some combination of these). All imaging devices (cameras, interferometers) are studying aspects of the spatial coherence (in various directions, and for different angular extents on the sky). All spectrally analyzing devices measure aspects of the
Light facilitates exploration of quantum phenomena that illuminate the basic properties of nature and also enables radical new technologies based on these phenomena. The critical features of quantum light that underpin the opportunities for discovery and application are exceptionally low noise and strong correlations. Rapid progress in both science and technology has been stimulated by adopting components developed for optical telecommunications and networking, such as highly efficient detectors, integrated photonic circuits, and waveguide- or nanostructure-based nonlinear optical devices. These provide the means to generate new quantum states of light and matter of unprecedented scale, containing many photons with quantum correlations across space and time. Notably, networks with only several tens of photons are already beyond what can be efficiently analyzed by current computers.