Quantum Optics Research Papers - Academia.edu (original) (raw)

Contextuality and entanglement are valuable resources for quantum computing and quantum information. Bell inequalities are used to certify entanglement; thus, it is important to understand why and how they are violated. Quantum mechanics and behavioral sciences teach us that random variables measuring the same content (the answer to the same Yes or No question) may vary, if measured jointly with other random variables. Alice and Bob raw data confirm Einsteinian non-signaling, but setting dependent experimental protocols are used to create samples of coupled pairs of distant outcomes and to estimate correlations. Marginal expectations, estimated using these final samples, depend on distant settings. Therefore, a system of random variables measured in Bell tests is inconsistently connected and it should be analyzed using a Contextuality-by-Default approach, what is done for the first time in this paper. The violation of Bell inequalities and inconsistent connectedness may be explained...

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- Mathematical Physics, Computer Science, Physics, Theoretical Physics

We studied the time evolution of a two-level electron system interacting with a single-mode bosonic field (i.e. photons, phonons). We found that in the adiabatic limit (i.e. electron motion fast and boson motion slow) it is possible to obtain a reduction in fluctuation for the position coordinate of boson and momentum coordinate as well, depending on the adiabatic potential. If the system is on a lower adiabatic sheet we obtain a reduction in momentum fluctuations. However, if the system is on an upper sheet the fluctuation in position coordinate (associated with the bosonic field) is reduced.

- by Titus Sandu and +1
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- Quantum Optics, Luminescence, Optical physics, Coherent States

We demonstrate efficient generation of collinearly propagating, highly nondegenerate photon pairs in a periodically-poled lithium niobate cw parametric downconverter with an inferred pair generation rate of 1.4*10^7/s/mW of pump power. Detection of an 800-nm signal photon triggers a thermoelectrically-cooled 20%-efficient InGaAs avalanche photodiode for the detection of the 1600-nm conjugate idler photon. Using single-mode fibers as spatial mode filters, we obtain a signal-conditioned idler-detection probability of about 3.1%.

- by Elliott Mason
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- Quantum Physics, Quantum Optics, Quantum entanglement, Avalanche Photodiodes

In this paper we study quantum mechanical phase distribution of some nonlinear optical phenomena in a general setting of interacting Fock space. We have investigated the optical phenomena of propagation through a nonlinear medium as in optical fiber and the process of photon absorption from a thermal beam. The input and output phase distribution have been investigated analytically in these two cases.

- by Arpita Chatterjee
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- Quantum Optics

The notion of f-oscillators generalizing q-oscillators is discussed. For the classical and quantum cases, an interpretation of the f-oscillator is provided as corresponding to a special nonlinearity of vibration for which the frequency of the oscillation depends on the energy. The f-coherent states generalizing the q-coherent states are constructed. Applied to quantum optics, the photon distribution function and photon number means and dispersions are calculated for the f-coherent states as well as the Wigner-Moyal function and Q-function. As an example, it is shown how this nonlinearity may affect the Planck's distribution formula.

- by G. Marmo
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- Physics, Quantum Optics, Russian, Oscillations

Quantum information is a rapidly advancing area of interdisciplinary research. It may lead to real-world applications for communication and computation unavailable without the exploitation of quantum properties such as nonorthogonality or entanglement. We review the progress in quantum information based on continuous quantum variables, with emphasis on quantum optical implementations in terms of the quadrature amplitudes of the electromagnetic field.

- by Gerd Leuchs
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- Quantum Optics, Quantum Information, Modern physics, Interdisciplinary research

Mixed states of samples of spin s particles which are symmetric under permutations of the particles are described in terms of their total collective spin quantum numbers. We use this description to analyze the influence on spin squeezing... more

- by Klaus Mølmer
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- Quantum Optics, Quantum Information, Mathematical Sciences, Physical sciences

We present a quantization scheme for the electromagnetic field in dispersive and lossy dielectrics with planar interfaces, incorporating propagation in all the spatial directions, and including both TE and TM polarized fields. Field quantization is carried out starting from a microscopic model for the polarization quanta interacting with the electromagnetic field. Dissipation is described by considering the coupling of the polarization quanta of the system with the reservoir oscillators in the usual Langevin approach. The method is applied to a semi-infinite medium and expressions for the electromagnetic field operators are obtained in the two different spatial regions, i.e., in the vacuum and in the dielectric. As a check of our quantization scheme, we have verified that the obtained vector potential operator and its conjugate momentum satisfy equal-time canonical commutation rules, giving rise to the prescribed transverse Dirac ␦ function.

- by Omar Di Stefano
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- Physics, Quantum Optics, Quantum Electrodynamics, Mathematical Sciences

Quantum logic gates require qubits that can interact strongly with each other and with external fields while minimizing unwanted coupling to the decohering environment. Neutral atoms trapped in a far-off resonance optical lattice satisfy these criteria. The adjustable parameters of the lattice (e.g., laser polarization, frequency, intensity) allow one to design interactions for which atoms interact strongly via dipole-dipole interactions

- by Gavin Brennen
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- Physics, Quantum Optics, Quantum Logic, Resonance

Radiating dipoles in photonic crystals. Kurt Busch 1,2 , Nipun Vats 1 , Sajeev John 1 , and Barry C. Sanders 3 1 Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario, Canada M5S 1A7 2 Institut ...

- by Sajeev John
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- Quantum Optics, Band Structure, Photonic Crystal, Dispersion Relation

Interest in dynamic behaviour of carriers in organic materials is motivated by possible applications that include organic thin film transistors, organic electroluminescent (EL) devices, and organic photo-conductors. It can also provide insight into modelling of carrier transport and trapping in organic semiconductors and insulators Here, we employ advanced SHG technique to probe and visualize real carrier motion in organic materials. This is a time-resolved microscopic optical SHG (TRM-SHG) technique that allows direct and selective probing of dynamic carrier motion in organic materials. TRM-SHG experiments using pentacene field effect transistors (FET) revealed dynamic changes of SHG intensity profiles arising from pentacene. Carrier velocity in organic solids is thus determined from the visualized carrier motion. We anticipate that this direct visualization technique will find wide application in the illustration of space charge field formation in organic and inorganic materials, including biomaterials and polymers.

- by Takaaki Manaka
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- Optics, Technology, Quantum Optics, Spectroscopy
- by Andrew Greentree
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- Optics, Technology, Quantum Optics, Spectroscopy

Quantum entanglement, a term coined by Erwin Schrodinger in 1935, is a mechanical phenomenon at the quantum level wherein the quantum states of two (or more) particles have to be described with reference to each other though these particles may be spatially separated. This phenomenon leads to paradox and has puzzled us for a long time. The behaviour of entangled particles is apparently inexplicable, incomprehensible and like magic at work. Locality has been a reliable and fruitful principle which has guided us to the triumphs of twentieth century physics. But the consequences of the local laws in quantum theory could seem "spooky" and nonlocal, with some theorists questioning locality itself. Could two subatomic particles on opposite sides of the universe be really instantaneously connected? Is any theory which predicts such a connection essentially flawed or incomplete? Are the results of experiments which demonstrate such a connection being misinterpreted? These question...

- by Bertrand Wong
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- Quantum Computing, Physics, Quantum Physics, Quantum Gravity

In quantum information, quantum systems and their properties offer unprecedented opportunities. Being able to harness additional degrees of freedom adds power and flexibility to quantum algorithms and protocols. In this work, we demonstrate that the radial transverse mode of a single photon constitutes one such degree of freedom. We do so by showing that we can tune the two-photon interference, a quintessential quantum effect and the basic constituent of many quantum protocols, by manipulating its radial transverse modal profiles. Our work, in addition to allowing for greater versatility of existing protocols and significantly increasing the information channel capacity, can inspire novel quantum information tasks.

- by Ebrahim Karimi
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- Quantum Physics, Quantum Optics, Mathematical Sciences, Physical sciences

System of 1/2 spin particles is observed repeatedly using Stern-Gerlach apparatuses with rotated orientations. Synthesis of such non-commuting observables is analyzed using maximum likelihood estimation as an example of quantum state reconstruction. Repeated incompatible observations represent a new generalized measurement. This idealized scheme will serve for analysis of future experiments in neutron and quantum optics.

- by Johann Summhammer
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- Quantum Optics, Quantum Mechanics, Mathematical Sciences, Maximum Likelihood

We report a quantum interference of nondiffracting beams by using photon pairs generated by spontaneous parametric down-conversion. The photon pairs transmitted by two double annular aperture produce fourth-order interference pattern along the transverse plane of detection as well as along the propagation distance. The latter presents a typical behaviour of the so-called Talbot effect . Introduction During the last few years, the properties of nondiffracting beams [1], also known as Bessel beams, have received attention by various authors. Recently, the superluminal behavior of these beams has been under investigation from a theoretical [2] and an experimental [3] point of view. An interesting self-imaging effect phenomenon, resulting from the superposition of two Bessel beams propagating in free space, has been predicted and experimentally demonstrated at a classical level [4]. On the other hand, the correlated photon pairs generated by spontaneous parametric down-conversion produc...

Magneto-optic surface plasmon resonance (MOSPR) based sensors are highly attractive as next generation biosensors. However, these sensors suffer from oxidation leading to degradation of performance, reproducibility of the sensor surface because of the difficulty of removing adsorbed materials, and degradation of sensor surface during surface cleaning, and these limit their applications. In this paper, I propose MOSPR-based biosensors with 0 to 15 nm thick inert polycarbonate laminate plastic as a protective layer and theoretically demonstrate the practicability of our approach in water-medium for three different probing samples: ethanol, propanol, and pentanol. I also investigate microstructure and magnetic properties. The chemical composition and ayered information of the sensor are investigated using X-ray reflectivity and X-ray diffraction analyses and these show distinct fcc-Au (111) phases, as dominated by the higher density of conduction electrons in Au as compared to Co. The magnetic characterization measured with the in-plane magnetic field to the sensor surface for both the as-deposited and annealed multilayers showed isotropic easy axis magnetization parallel to the multilayer interface at a saturating magnetic field of < 100 Oe. The sensor showed a maximum sensitivity of 5.5 × 10 4 % / RIU for water-ethanol media and the highest detection level of 2.5×10-8 for water-pentanol media as the protective layer is increased from 0 to 15 nm.

- by Conrad Rizal
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- Quantum Optics, Nanoelectronics, Bio and Nano Photonics

As a step toward absolute calibration of optical tweezers, a first-principles theory of trapping forces with no adjustable parameters, corrected for spherical aberration, is experimentally tested. Employing two very different setups, we find generally very good agreement for the transverse trap stiffness as a function of microsphere radius for a broad range of radii, including the values employed in practice, and at different sample chamber depths. The domain of validity of the WKB (``geometrical optics'') approximation to the theory is verified. Theoretical predictions for the trapping threshold, peak position, depth variation, multiple equilibria, and ``jump'' effects are also confirmed.

- by Herch Nussenzveig
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- Engineering, Quantum Optics, Physical sciences, Solar Radiation Pressure
- by Tenio Popmintchev
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- Optics, Technology, Quantum Optics, Nonlinear Optics

We generate a pair of entangled beams from the interference of two amplitude squeezed beams. The entanglement is quantified in terms of EPR-paradox [1] and inseparability[2] criteria, with observed results of ∆ 2 X + x|y ∆ 2 X − x|y = 0.58±0.02 and ∆ 2 X + x±y ∆ 2 X − x±y = 0.44±0.01, respectively. Both results clearly beat the standard quantum limit of unity. We experimentally analyze the effect of decoherence on each criterion and demonstrate qualitative differences. We also characterize the number of required and excess photons present in the entangled beams and provide contour plots of the efficacy of quantum information protocols in terms of these variables.

- by H.-a. Bachor
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- Quantum Computing, Physics, Information Theory, Quantum Optics

Absorption and dispersion properties of a V-shaped quantum-dot molecule are investigated. The effect of
decay-induced interference and inter-dot tunneling on phase control of the absorption and the dispersion
is then discussed. We find that in the presence of decay-induced interference or inter-dot tunneling the
group velocity of a light pulse is completely phase dependant. The required switching times for switching
the group velocity of a light pulse from subluminal to superluminal pulse propagation is then discussed.

- by Mohammad Reza (Bahman) Mehmannavaz
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- Quantum Optics, Quantum Dots, Switching Time

Page 1. Quantum Communications: Present Status and Future Prospects Prem Kumar, Joseph B. Altepeter, and Matthew A. Hall ... 16 J. Chen, et al. “Demonstration of a Quantum Controlled-NOT Gate in the Telecom Band,” Phys. Rev. Lett. 100,... more

- by Prem Kumar
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- Physics, Quantum Optics, Quantum Information, Optical fiber
- by Sean F Johnston
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- History of Science and Technology, Optics, Quantum Optics, History of Technology

A superluminal quantum-vortex model of the electron and the positron is produced from a superluminal double-helix model of the photon during electron-positron pair production. The two oppositely-charged (with Q = ±e sqrt (2/α) = 16.6e) open-helix spin-½ half-photons compose the double-helix photon. These half-photons separate and curl up their separated superluminal single-helical trajectories to form an electrically-charged superluminal closed-helix spin-½ quantum-vortex electron model and a corresponding positron model. The helical radius and the Dirac equation's zitterbewegung angular frequency of the quantum vortex electron and positron models equal the helical radius and zitterbewegung angular frequency of the two spin-½ half-photons, each of energy E = mc^2 , that composed the double-helix photon model of energy E = 2mc^2 from which the electron and positron models were produced. The photon and electron models are also compatible when a photon of energy E > 2mc^2 produces a relativistic electron-positron pair. Implications of the quantum vortex electron model for electron stability are discussed.

Single-photon detectors based on superconducting nanowires (SSPDs or SNSPDs) have rapidly emerged as a highly promising photon-counting technology for infrared wavelengths. These devices offer high efficiency, low dark counts and excellent timing resolution. In this review, we consider the basic SNSPD operating principle and models of device behaviour. We give an overview of the evolution of SNSPD device design and the improvements in performance which have been achieved. We also evaluate device limitations and noise mechanisms. We survey practical refrigeration technologies and optical coupling schemes for SNSPDs. Finally we summarize promising application areas, ranging from quantum cryptography to remote sensing. Our goal is to capture a detailed snapshot of an emerging superconducting detector technology on the threshold of maturity.

- by David Pappas
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- Engineering, Materials Engineering, Condensed Matter Physics, Remote Sensing

- by Alessandro Gaggero and +1
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- Engineering, Materials Engineering, Condensed Matter Physics, Remote Sensing
- by Johannes Kiefer
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- Quantum Optics, Optical physics
- by LUKAS ILIADAKIS
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- Field Theory, Quantum Physics, Quantum Optics, Quantum Field Theory
- by Lin Zhang
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- Quantum Physics, Quantum Optics
- by DERBOV VLADIMIR
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- Quantum Physics, Quantum Optics, Light field, Coherent States

With the advancement of wireless communication, optical wireless communication (OWC) has evolved into a communication method with a wide range of applications. However, different nonlinear effects in optical wireless communication will cause significant signal processing issues and degrade the system's performance. When paired with the visible light of machine learning methods, machine learning has a lot of potential for tackling nonlinear problems. Communication technology must be extremely valuable in terms of research. Traditional machine learning techniques like KGmeans, DBSCAN, and support vector machines (SVM) have been proven to perform well in pre-equalization, post-equalization, anti-system jitter, and phase correction in studies. The aforementioned methodologies are discussed and introduced, as well as their applications in the field of optical wireless communication signal processing, in the hopes of providing a reference for machine learning to handle numerous nonlinear problems in optical wireless communication. Because of its high nonlinear fitting capabilities, the deep neural network (DNN) can help the OWC system operate even better.

- by IAEME Publication
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- Quantum Optics, Machine Learning, Owc, Artifical Neural Networks

In this paper we raise questions about the reality of computational quantum parallelism. Such questions are important because while quantum theory is rigorously established, the hypothesis that it supports a more powerful model of computation remains speculative. More specifically, we suggest the possibility that the seeming computational parallelism offered by quantum superpositions is actually effected by gate-level parallelism in the reversible implementation of the quantum operator. In other words, when the total number of logic operations is analyzed, quantum computing may not be more powerful than classical. This fact has significant public policy implications with regard to the relative levels of effort that are appropriate for the development of quantumparallel algorithms and associated hardware (i.e., qubit-based) versus quantum-scale classical hardware.

- by marco lanzagorta
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- Quantum Computing, Quantum Optics, Quantum Information, Quantum Theory

In this paper we have studied the statistical and squeezing proprieties of light produced by superposition of a pair of single-mode squeezed chaotic light beams. Applying density operator of single-mode squeezed chaotic state; we obtain the anti-normal order characteristics function which enables us to find the Q function. With the resulting Q function, we calculate the photon statistics and the Quadrature squeezing for single-mode squeezed chaotic light. Moreover applying Q function of single-mode squeezed chaotic state the superposed light beams would be driven. With the resulting Q function we calculated the photon statics and the quadrature squeezing for superposed light beams. To get the maximum squeezing to be 95%, for nth = 0 and r = 1.5. 1 Introduction The most important quantum states of light are chaotic state, coherent state and squeezed state. Chaotic state is one of the classical features of light with super-Poissonian photon statics. And its best example is thermal light. The coherent state is a specific superposition of number states which does not possess number of photons as well as it is known by minimum uncertainty and poissonian photon statistics. Squeezed state satisfies non-classical feature of light, with sub-poissonian photon statistics [1]-[4]. The quantum distribution of radiation is the core idea in quantum optics. This used to describe the quantum properties of light. Some of them are the P function, the Wigner function and the Q functions. The P-function is c-number function with the anti-normal order density operator over π. And used to describe the superposition of two light beams with different states but having the same frequency. The Wigner function is the c-number function corresponding to the symmetric order density operator over π. The Q function is the most widely used one because, it is used to describe the superposition of two light beams with the same frequency but may be in the same or different states. This is described in terms of normally ordered density operator divided by π [5].

† These authors contributed equally to this work.

- by Remi Riviere
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- Quantum Optics, Science, Multidisciplinary, Electromagnetically Induced Transparency

The squeezing, and statistical properties of a superposed light beam produced by a lambda type three-level lasers configuration have been studied. We have determined the quadrature variances mean as well as variance photon number for cavity modes with the aid of the solutions of c-number Langevin equations associated with the normal order. We have carried out our analysis a light in a squeezing state can be produced by the system under consideration under the condition that the cavity decay constant is larger than the linear gain coefficient and the squeezing occurs in the minus-quadrature. Furthermore, we also obtain with the aid of the Q-functions and the density operator the superposition beam, and superposed light beams are determined in quadrature variance and mean photon number. The result shows that the mean photon number and the quadrature variance of the superposed light beam are the sum of the mean photon number and the quadrature variance of the constituent light beams.

- by Takele T E S H O M E Somano
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- Quantum Optics

In this paper we present a novel construction of an active quenching circuit intended for single photon detection. For purpose of evaluation, we have combined this circuit with a standard avalanche photodiode C30902S to form a single photon detector. A series of measurements, presented here, show that this single photon detector has a dead time of less than 40ns, maximum random counting frequency of over 14MHz, low after pulsing, detection efficiency of over 20% and a good noise performance. This simple and robust active quenching circuit can be built from of-the-shelf electronic components and needs no complicated adjustments.

- by Mario Stipčević
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- Mechanical Engineering, Quantum Optics, Applied Optics, Optical physics

The magnetic dipole field geometry of subatomic elementary particles like the electron differs from the classical macroscopic field imprint of a bar magnet. It resembles more like an eight figure or else joint double quantum-dots instead of the classical, spherical more uniform field of a bar magnet. This actual subatomic quantum magnetic field of an electron at rest, is called Quantum Magnet or else a Magneton. It is today verified experimentally by quantum magnetic field imaging methods and sensors like SQUID scanning magnetic microscopy of ferromagnets and also seen in Bose-Einstein Condensates (BEC) quantum ferrofluids experiments. Normally, a macroscale bar magnet should behave like a relative giant Quantum Magnet with identical magnetic dipole field imprint since all of its individual magnetons collectively inside the material, dipole moments are uniformly aligned forming the total net field of the magnet. However due to Quantum Decoherence (QDE) phenomenon at the macroscale and macroscopic magnetic field imaging sensors limitations which cannot pickup these rapid quantum magnetization fluctuations, this field is masked and not visible at the macroscale. By using the relative inexpensive submicron resolution Ferrolens quantum magnetic optical superparamagnetic thin film sensor for field real time imaging and method we have researched in our previous publications, we can actually make this net magneton field visible on macroscale magnets. We call this net total field herein, Quantum Field of Magnet (QFM) differentiating it therefore from the field of the single subatomic magneton thus quantum magnet. Additionally, the unique potential of the Ferrolens device to display also the magnetic flux lines of this macroscopically projected giant Magneton gives us the opportunity for the first time to study the individual magnetic flux lines geometrical pattern that of a single subatomic magneton. We describe this particular magnetic flux of the magneton observed, quantum magnetic flux. Therefore an astonishing novel observation has been made that the Quantum Magnetic Field of the Magnet-Magneton (QFM) consists of a dipole vortex shaped magnetic flux geometrical pattern responsible for creating the classical macroscopic N-S field of magnetism as a tension field between the two polar quantum flux vortices North and South poles. A physical interpretation of this quantum decoherence mechanism observed is analyzed and presented and conclusions made showing physical evidence of the quantum origin irrotational and therefore conservative property of magnetism and also demonstrating that ultimately magnetism at the quantum level is an energy dipole vortex phenomenon.

- by Emmanouil Markoulakis
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- Physics, Condensed Matter Physics, Electromagnetism, Quantum Physics

We present a wave-function approach to the study of the evolution of a small system when it is coupled to a large reservoir. Fluctuations and dissipation originate in this approach from quantum jumps that occur randomly during the time evolution of the system. This approach can be applied to a wide class of relaxation operators in the Markovian regime, and it is equivalent to the standard master-equation approach. For systems with a number of states N much larger than unity this Monte Carlo wave-function approach can be less expensive in terms of calculation time than the master-equation treatment. Indeed, a wave function involves only N components, whereas a density matrix is described by N 2 terms. We evaluate the gain in computing time that may be expected from such a formalism, and we discuss its applicability to several examples, with particular emphasis on a quantum description of laser cooling. 0740-3224/93/030524-15$05.00

- by Klaus Mølmer
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- Applied Mathematics, Quantum Optics, Quantum Theory, Monte Carlo
- by Jurgen Michel
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- Optics, Technology, Quantum Optics, Spectroscopy
- by Jack Sarfatti
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- Quantum Computing, Quantum Physics, Quantum Chemistry, Quantum Gravity

The No-communication Theorem has been seen as the bar to communication by quantum state collapse. The essence of this theory is the procedure of taking the partial trace on an entangled, hence inseparable multi-particle system. This mathematical procedure applied unthinkingly, strikes out the off-diagonal elements from the ensemble density matrix and renders the reduced trace matrix representative of a mixed state. Decoherence theory is able to justify this mathematical procedure and we review it to show: the partial trace results for both unitary and non-unitary processes (hence measurement) on one, several or all particles of the ensemble; and that a unitary process keeps interference terms in the trace reduced matrix.

- by Remi Cornwall
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- Quantum Physics, Philosophy of Science, Quantum Optics, Relativity

Quantum physics was invented to account for two fundamental features of measurement resultstheir discreetness and randomness. Emblematic of these features is Bohr's idea of quantum jumps between two discrete energy levels of an atom 1. Experimentally, quantum jumps were first observed in an atomic ion driven by a weak deterministic force while under strong continuous energy measurement 2-4. The times at which the discontinuous jump transitions occur are reputed to be fundamentally unpredictable. Can there be, despite the indeterminism of quantum physics, a possibility to know if a quantum jump is about to occur or not? Here, we answer this question affirmatively by experimentally demonstrating that the jump from the ground to an excited state of a superconducting artificial three-level atom can be tracked as it follows a predictable "flight," by monitoring the population of an auxiliary energy level coupled to the ground state. The experimental results demonstrate that the jump evolution when completed is continuous, coherent, and deterministic. Furthermore, exploiting these features and using real-time monitoring and feedback, we catch and reverse a quantum jump mid-flight, thus deterministically preventing its completion. Our results, which agree with theoretical predictions essentially without adjustable parameters, support the modern quantum trajectory theory 5-9 and provide new ground for the exploration of real-time intervention techniques in the control of quantum systems, such as early detection of error syndromes.

- by H. Carmichael
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- Quantum Computing, Condensed Matter Physics, Quantum Physics, Quantum Optics

For a long time, one of my dreams was to describe the nature of uncertainty axiomatically, and it looks like I've finally done it in my co∼eventum mechanics! Now it remains for me to explain to everyone the co∼eventum mechanics in the most approachable way. This is what I'm trying to do in this work. The co∼eventum mechanics is another name for the co∼event theory, i.e., for the theory of experience and chance which I axiomatized in 2016 [1, 2]. In my opinion, this name best reflects the co∼event-based idea of the new dual theory of uncertainty, which combines the probability theory as a theory of chance, with its dual half, the believability theory as a theory of experience. In addition, I like this new name indicates a direct connection between the co∼event theory and quantum mechanics, which is intended for the physical explanation and description of the conict between quantum observers and quantum observations [4]. Since my theory of uncertainty satises the Kolmogorov axioms of probability theory, to explain this co∼eventum mechanics I will use a way analogous to the already tested one, which explains the theory of probability as a theory of chance describing the results of a random experiment. The simplest example of a random experiment in probability theory is the " tossing a coin ". Therefore, I decided to use this the simplest random experiment itself, as well as the two its analogies: the " "flipping a coin " and the " spinning a coin " to explain the co∼eventum mechanics, which describes the results of a combined experienced random experiment. I would like to resort to the usual for the probability theory " coin-based " analogy to explain (and first of all for myself) the logic of the co∼eventum mechanics as a logic of experience and chance. Of course, this analogy one may seem strange if not crazy. But I did not come up with a better way of tying the explanations of the logic of the co∼eventum mechanics to the coin-based explanations that are commonly used in probability theory to explain at least for myself the logic of the chance through a simple visual " coin-based " model that clarifies what occurs as a result of a combined experienced random experiment in which the experience of observer faces the chance of observation. I hope this analogy can be useful not only for me in understanding the co∼eventum mechanics.

Th e generation of femtosecond optical pulses 1 has opened up a range of applications from real-time monitoring of chemical reactions through to ultrahigh-bit-rate optical communications 2 , and has led to new concepts in femtosecond optical networking, signal processing and transmission. In fact, lasers operating at multigigahertz repetition rates are now becoming key components for high-capacity telecommunication systems, photonic switching devices, optical interconnects, clocks for very-large-scale integrated microprocessors and high-speed electro-optic sampling systems.

- by Edik Rafailov
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- Optics, Technology, Quantum Optics, Spectroscopy

By the 1950's it was generally agreed that "the photon's wave and quanta (particle) qualities are two observable aspects of a single phenomenon, and cannot be described by any mechanical model." (Joos, George. Theoretical Physics. London and Glasgow: Blackie and Son Ltd. (1951). In other words, it is somehow both a wave and a particle, but the most recent research in optics has shown that it can, in fact be "be described by [a quite simple] mechanical model"-- a particle that travels along a tight spiral path.

- by Gareth F Morgan
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- Quantum Optics, Theoretical Cosmology, Light
- by Aephraim Steinberg
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- Quantum Optics, Quantum Mechanics, Tunneling, Scientific American

Although the postulate of " photon-having-zero-rest-mass " became over the years a sort of " dogma " , routinely repeated in thousands of physics textbooks and scientific articles, great physicists like two " fathers " of Quantum Mechanics: Erwin Schrödinger and Louis De Broglie, never believed that photons were really " massless " at rest, and many other remarkable physicists challenged this conviction as well. In recent years (2001-2005), the experiments through which Lene Westengarten Hau succeeded in slowing down, stopping, and making restart a laser light pulse by making it pass through optical molasses and ultra-cold sodium vapors of BEC (Bose-Einstein Condensates) can be interpreted as final and persuading evidence that photons –being both particles and e.m. waves-do possess a rest mas and they can be damped in " classical " and quantum ways as damped harmonic oscillators (classical) and superposing waves (QM). Therefore the speed of light is neither an universal constant (c), nor it is " invariant under Lorentz' transformations " , thereby destroying the 2 main pillars of Einstein's SR (Special Relativity). " There must be no barriers to freedom of inquiry. There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. " (J. Robert Oppenheimer)

- by Alberto Miatello
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- Condensed Matter Physics, Quantum Physics, Quantum Optics, Relativity

Interference with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory fields technique used in atomic clocks. Atom interferometry is now reaching maturity as a powerful art with many applications in modern science. In this review the basic tools for coherent atom optics are described including diffraction by nanostructures and laser light, three-grating interferometers, and double wells on atom chips. Scientific advances in a broad range of fields that have resulted from the application of atom interferometers are reviewed. These are grouped in three categories: ͑i͒ fundamental quantum science, ͑ii͒ precision metrology, and ͑iii͒ atomic and molecular physics. Although some experiments with Bose-Einstein condensates are included, the focus of the review is on linear matter wave optics, i.e., phenomena where each single atom interferes with itself.

- by Dave Pritchard
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- Physics, Quantum Physics, Chemistry, Quantum Optics