Statistical properties of ideal photons in a two-dimensional dye-filled spherical cap cavity

Within the framework of quantum statistical mechanics,we have proposed an exact analytical solution to the problemof Bose-Einstein condensation(BEC)of harmonically trapped two-dimensional(2D)ideal photons.We utilize this analyticalsolution to investigate the statistical properties of ideal photons in a 2D dye-filled spherical cap cavity.The resultsof numerical calculation of the analytical solution agree completely with the foregoing experimental results in the BEC ofharmonically trapped 2D ideal photons.The analytical expressions of the critical temperature and the condensate fractionare derived in the thermodynamic limit.It is found that the 2D critical photon number is larger than the one-dimensional(1D)critical photon number by two orders of magnitude.The spectral radiance of a 2D spherical cap cavity has a sharppeak at the frequency of the cavity cutoff when the photon number exceeds the critical value determined by a temperature.

Performance validation of High Mountain Asia 8-meter Digital Elevation Model using ICESat-2 geolocated photons

High Mountain Asia(HMA),recognized as a third pole,needs regular and intense studies as it is susceptible to climate change.An accurate and high-resolution Digital Elevation Model(DEM)for this region enables us to analyze it in a 3D environment and understand its intricate role as the Water Tower of Asia.The science teams of NASA realized an 8-m DEM using satellite stereo imagery for HMA,termed HMA 8-m DEM.In this research,we assessed the vertical accuracy of HMA 8-m DEM using reference elevations from ICESat-2 geolocated photons at three test sites of varied topography and land covers.Inferences were made from statistical quantifiers and elevation profiles.For the world’s highest mountain,Mount Everest,and its surroundings,Root Mean Squared Error(RMSE)and Mean Absolute Error(MAE)resulted in 1.94 m and 1.66 m,respectively;however,a uniform positive bias observed in the elevation profiles indicates the seasonal snow cover change will dent the accurate estimation of the elevation in this sort of test sites.The second test site containing gentle slopes with forest patches has exhibited the Digital Surface Model(DSM)features with RMSE and MAE of 0.58 m and 0.52 m,respectively.The third test site,situated in the Zanda County of the Qinghai-Tibet,is a relatively flat terrain bed,mostly bare earth with sudden river cuts,and has minimal errors with RMSE and MAE of 0.32 m and 0.29 m,respectively,and with a negligible bias.Additionally,in one more test site,the feasibility of detecting the glacial lakes was tested,which resulted in exhibiting a flat surface over the surface of the lakes,indicating the potential of HMA 8-m DEM for deriving the hydrological parameters.The results accrued in this investigation confirm that the HMA 8-m DEM has the best vertical accuracy and should be of high use for analyzing natural hazards and monitoring glacier surfaces.

The Coulomb Resonances, the Quasi-Real Photons and Electro-Disintegration of Nuclei by High-Energy Electrons

Various aspects of the influence of the quasi-real photons and the Coulomb resonances on the formation of the crosssection of inelastic scattering of high energy electrons on atomic nuclei are investigated. Emiss is the energy that disappears in the processes of knocking-on of protons in the reactions . A new hypothesis that interprets the origin of the energy losses is proposed. Specific experiments that can confirm or refute this hypothesis are proposed as well. The “regularized” cross-sections of electro-disintegration of nuclei by high-energy electrons are calculated in the framework of the nuclear shell model. It is shown that for the experimental verification of the existence of Coulomb resonances, it is necessary to investigate the processes at relatively small angles of scattering. The peculiarities of numerical methods that are crucial in the investigation of inelastic scattering of high-energy electrons on nuclei in the framework of the nuclear shell model are analyzed in this work as well. The cross-sections of the scattering of high-energy electrons on the angle are calculated. It is shown that the orthogonality of the wave functions of a knocked-on proton in the initial and final states plays an important role in the interpretation of this process.

Economical quantum secure direct communication network with single photons

In this paper a scheme for quantum secure direct communication （QSDC） network is proposed with a sequence of polarized single photons. The single photons are prepared originally in the same state （0） by the servers on the network, which will reduce the difficulty for the legitimate users to check eavesdropping largely. The users code the information on the single photons with two unitary operations which do not change their measuring bases. Some decoy photons, which are produced by operating the sample photons with a Hadamard, are used for preventing a potentially dishonest server from eavesdropping the quantum lines freely. This scheme is an economical one as it is the easiest way for QSDC network communication securely.

Two narrow bandwidth photons interfering in an electromagnetically induced transparency (EIT) system

In this paper, we have analysed in detail the quantum interference of the degenerate narrowband two-photon state by using a Mach-Zehnder interferometer, in which an electromagnetically induced transparency （EIT） medium is placed in one of two interfering beams. Our results clearly show that it is possible to coherently keep the quantum state at a single photon level in the EIT process, especially when the transparent window of the EIT medium is much larger than the bandwidth of the single photon. This shows that the EIT medium is possibly a kind of memory or repeater for the narrowband photons in the areas of quantum communication and quantum computer. This kind of experiment is feasible within the current technology.

Cavity optomechanics： Manipulating photons and phonons towards the single-photon strong coupling

Cavity optomechanical systems provide powerful platforms to manipulate photons and phonons, open potential ap- plications for modern optical communications and precise measurements. With the refrigeration and ground-state cooling technologies, studies of cavity optomechanics are making significant progress towards the quantum regime including non- classical state preparation, quantum state tomography, quantum information processing, and future quantum internet. With further research, it is found that abundant physical phenomena and important applications in both classical and quan- tum regimes appeal as they have a strong optomechanical nonlinearity, which essentially depends on the single-photon optomechanical coupling strength. Thus, engineering the optomechanical interactions and improving the single-photon optomechanical coupling strength become very important subjects. In this article, we first review several mechanisms, theoretically proposed for enhancing optomechanical coupling. Then, we review the experimental progresses on enhancing optomechanical coupling by optimizing its structure and fabrication process. Finally, we review how to use novel structures and materials to enhance the optomechanical coupling strength. The manipulations of the photons and phonons at the level of strong optomechanical coupling are also summarized.

Quantum frequency down-conversion of single photons at 1552 nm from single InAs quantum dot

Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single photons emitted from single In As quantum dot at 864 nm is down converted to 1552 nm by using a fiber-coupled periodically poled lithium niobate（PPLN） waveguide and a 1.95 μmm pump laser, and the frequency conversion efficiency is ~40%. The singlephoton purity of quantum dot emission is preserved during the down-conversion process, i.e., g^（（2））（0）, only 0.22 at 1552 nm.This present technique advances the Ⅲ-Ⅴ semiconductor quantum dots as a promising platform for long-distance quantum communication.

α-clustering effect on flows of direct photons in heavy-ion collisions

In this study,we reconstruct theγ-photon energy spectrum,which is in good agreement with the experimental data of ^(86)Kr+^(12)C at E/A=44 Me V within the framework of the modified EQMD model.The directed and elliptic flows of free protons and direct photons were investigated by considering theα-clustering structure of ^(12)C.Compared with free protons,direct photon flows provide clearer information about the early stage of a nuclear reaction.The difference in the collective flows between different configurations of ^(12)C is observed in this study.This indicates that the collective flows of direct photons are sensitive to the initial configuration.Therefore,theγbremsstrahlung process might be taken as an alternative probe to investigate theα-clustering structure in a light nucleus from heavy-ion collisions within the Fermienergy region.

Slow photons for solar fuels

Converting solar energy into hydrogen and hydrocarbon fuels through photocatalytic H2production and CO2photoreduction is a highly promising approach to address growing demand for clean andrenewable energy resources.However,solar‐to‐fuel conversion efficiencies of current photocatalysts are not sufficient to meet commercial requirements.The narrow window of solar energy that can be used has been identified as a key reason behind such low photocatalytic reaction efficiencies.The use of photonic crystals,formed from multiple material components,has been demonstrated to be an effective way of improving light harvesting.Within these nanostructures,the slow‐photon effect,a manifestation of light‐propagation control,considerably enhances the interaction between light and the semiconductor components.This article reviews recent developments in the applications of photonic crystals to photocatalytic H2production and CO2reduction based on slow photons.These advances show great promise for improving light harvesting in solar‐energy conversion technologies.

Multifunctional inverse sensing by spatial distribution characterization of scattering photons

Inverse sensing is an important research direction to provide new perspectives for optical sensing. For inverse sensing, the primary challenge is that scattered photon has a complicated profile, which is hard to derive a general solution. Instead of a general solution, it is more feasible and practical to derive a solution based on a specific environment. With deep learning, we develop a multifunctional inverse sensing approach for a specific environment. This inverse sensing approach can reconstruct the information of scattered photons and characterize multiple optical parameters simultaneously. Its functionality can be upgraded dynamically after learning more data. It has wide measurement range and can characterize the optical signals behind obstructions. The high anti-noise performance, flexible implementation, and extremely high threshold to optical damage or saturation make it useful for a wide range of applications, including self-driving car, space technology, data security, biological characterization, and integrated photonics.

Influence of Characteristics of Substance on Parameters of Interaction of Photons High Energy with Free Electrons

Various variants of interaction of photons high energy with free electrons in substance are investigated. It is shown, that among these variants, in substance can be observed: absorption of a photon by electron, coherent and not coherent scattering of photons, a stop electron after interaction with a photon. Dependence of change of length of a wave of a photon after interaction with electron from parameters of substance and speed of movement electron is found.

Efficient quantum private comparison protocol utilizing single photons and rotational encryption

As a branch of quantum secure multiparty computation,quantum private comparison is applied frequently in many fields,such as secret elections,private voting,and identification.A quantum private comparison protocol with higher efficiency and easier implementation is proposed in this paper.The private secrets are encoded as single polarized photons and then encrypted with a homomorphic rotational encryption method.Relying on this method and the circular transmission mode,we implement the multiplexing of photons,raising the efficiency of our protocol to 100%.Our protocol is easy to realize since only single photons,unitary operation,and single-particle measurement are introduced.Meanwhile,the analysis shows that our protocol is also correct and secure.

An Electron Model Consistent with Electron-Positron Pair Production from High Energy Photons

This is a rotating charge loop model of an electron which explains the electron’s de Broglie base frequency to an accuracy of over 6 decimal places. The model also predicts the magnetic moment of the electron to over 6 decimal places and helps explain the transition from a purely electromagnetic photon to a fermion state of matter. The model also explains how charge and spin are conserved in the transition. Finally, this concept might be extended to explain the muon and tau higher energy states of the electron as well.

The “Dynamic Gravitation of Photons: A Hitherto Unknown Physical Quantity”. New Aspects on the Physics of Photons

In order to explore the nature of photons, no doubts can be allowed to exist concerning the “physics of photons”. While static gravitation plays no role in the physics of photons, this paper will show that the previously unknown nonbaryonic dynamic gravitation of photons determines not only the external physical behaviour of photons but also, in particular, the hitherto unknown physical events occurring within the photons themselves. For this reason, the paper places particular emphasis on dynamic gravitation as a new hitherto unknown physical quantity. Moreover the new type of gravitation postulated here also provides a plausible explanation of the mysterious nonbaryonic dark matter. As no generally accepted scientific explanation of the creation and essence of dark matter exists to date, it is to be anticipated that the nonbaryonic dynamic gravitation of photons is of general interest to physicists as well as cosmologists and may serve to initiate a general debate among them. Furthermore, this paper will also show that there exists a close mutual relationship between electrodynamics dynamic gravitation static gravitation electrostatics electrodynamics (refer to paragraph 4). Due to the fact that the insights into the relationship between photons and their dynamic gravitation have not been described by any other author to date, there exists only a few references that I can cite in support of my paper.

Long Range, Long Lived and Gauge Invariant Massive Photons via Stückelberg Scalar Coupling

It is largely believed (or strongly assumed) that photons are massless particles and the most compelling evidence there—it is said—is found in the manifestations of photons being long ranged and long lived particles. As we have done before, albeit, with a much better and clear insight in the present than before;we argue herein that massive photons can still enjoy the special and rare privilege of travelling at the speed of light c while being long ranged, long lived and most of all, obeying the much desired gauge symmetry. This we achieve by breaking the traditional Lorenz gauge and in its place, we introduce a new Special Gauge Condition (SGC) that does the work of assuring the photon its longevity, long range-ness and that it [photon] propagates at the speed c. However, the most melancholic outcome of our investigation is that if the present scheme is what subtle Nature has chosen to endow the photon a non-zero mass so that it [photon] still obeys gauge invariance, is long ranged, long lived and travels at the sacred speed c;then, this non-zero photon mass may be very difficult, if not impossible to measure. We use the equations developed to investigate Lorentz violation in ?-ray bursts.

Geant4 Comparative Study of Affecting Different Parameters on Optical Photons Related to the Plastic Scintillation Detector

In this research, different parameters of plastic scintillator detector were investigated by Geant4 simulation toolkit. These parameters consisted of radius, length and position of PMT as well as surface reflective type and finish options. Furthermore, response time distributions of two organic plastic materials were studied. The results indicated that collecting optical photons has a linear relationship with PMT radius head. Also, the vertical location of PMT has a non-linear relationship with the optical photons collection. However, the collection decreased by increasing PMT length or moving PMT head horizontal position. The response functions of two plastic scintillator materials were in good agreement with experimental published results. Also, Geant4 radiation transport code can simulate incident radiation photon and predict subsequent events to the PMT head very well. The results indicated that BC-404 has faster scintillation properties versus BC-400 organic scintillator materials. Comparison between Geant4 outputs illustrates that the best reflector material and surface finish type for optical photons is ground TiO2.

Hard Photons from a Non-Equilibrated Quark-Gluon Plasma with Finite Baryon Density at a Two-Loop Level

We study hard photon production from a two-loop level （bremsstrahlung and annihilation with scattering） in a chemically equilibrating quark-gluon plasma at finite baryon density based on Jüttner distribution of partons of the system. We find that the photon yield from the two-loop level increases obviously with the increasing initial quark chemical potential.

Calculations of the transmitted gamma photons through infinite slabs

The intensity and number of transmitted multiple scattered photons are calculated for 0.123, 0.320, 0.511,0.662, and 1.115 Me V gamma photons normally incident on slabs of carbon, aluminum, iron, copper, water, muscle,bone, and concrete with thicknesses varying from 1 to 10 mean free paths. The dependence of the transmission probability and energy distribution on the incident energy and material are examined. In general, the obtained results show good agreement with the other values calculated by the Monte Carlo method.

Fabrication and integration of photonic devices for phase-change memory and neuromorphic computing

In the past decade,there has been tremendous progress in integrating chalcogenide phase-change materials(PCMs)on the silicon photonic platform for non-volatile memory to neuromorphic in-memory computing applications.In particular,these non von Neumann computational elements and systems benefit from mass manufacturing of silicon photonic integrated circuits(PICs)on 8-inch wafers using a 130 nm complementary metal-oxide semiconductor line.Chip manufacturing based on deep-ultraviolet lithography and electron-beam lithography enables rapid prototyping of PICs,which can be integrated with high-quality PCMs based on the wafer-scale sputtering technique as a back-end-of-line process.In this article,we present an overview of recent advances in waveguide integrated PCM memory cells,functional devices,and neuromorphic systems,with an emphasis on fabrication and integration processes to attain state-of-the-art device performance.After a short overview of PCM based photonic devices,we discuss the materials properties of the functional layer as well as the progress on the light guiding layer,namely,the silicon and germanium waveguide platforms.Next,we discuss the cleanroom fabrication flow of waveguide devices integrated with thin films and nanowires,silicon waveguides and plasmonic microheaters for the electrothermal switching of PCMs and mixed-mode operation.Finally,the fabrication of photonic and photonic–electronic neuromorphic computing systems is reviewed.These systems consist of arrays of PCM memory elements for associative learning,matrix-vector multiplication,and pattern recognition.With large-scale integration,the neuromorphic photonic computing paradigm holds the promise to outperform digital electronic accelerators by taking the advantages of ultra-high bandwidth,high speed,and energy-efficient operation in running machine learning algorithms.

Energy distributions of multiple backscattered photons in materials

Backscattering of gamma photons from a material is of fundamental importance in radiation shielding,industrial and medical applications, radiation dosimetry,and non-destructive testing. In Compton scattering, incident photons undergo multiple scatterings within the material(target) before exiting. Gamma photons continue to soften in energy as the number of scatterings increases in a thick target; in other words, the energy of gamma photons decreases as the scatterings increase in case of a thick target and results in the generation of singly and multiply scattered events. In this work, the energy distribution of backscattered gamma photons with backscattering intensity and energy probabilities were calculated by using the Monte Carlo method for metallic, biological, and shielding materials with various thicknesses of slab geometry. The materials under study were targeted with gamma photons of 0.279, 0.662, 1.250, and 2.100 Me V energies. In addition, the energy distributions of multiply scattered gamma photons were studied for materials with infinite geometry.The results are presented and discussed in detail by comparing with other Monte Carlo calculations.