Quantum Space Research Articles

Photon quantization in cosmological spaces

Canonical quantization of the photon—a free massless vector field—is considered in cosmological spacetimes in a two-parameter family of linear gauges that treat all the vector potential components on equal footing. The goal is setting up a framework for computing photon two-point functions appropriate for loop computations in realistic inflationary spacetimes. The quantization is implemented without relying on spacetime symmetries, but rather it is based on the classical canonical structure. Special attention is paid to the quantization of the canonical first-class constraint structure that is implemented as the condition on the physical states. This condition gives rise to subsidiary conditions that the photon two-point functions must satisfy. Some of the de Sitter space photon propagators from the literature are found not to satisfy these subsidiary conditions, bringing into question their consistency. Published by the American Physical Society 2024

Weak cosmic censorship conjecture and black hole shadow for black hole with generalized uncertainty principle

Based on string theory, loop quantum gravity, black hole physics, and other theories of quantum gravity, physicists have proposed generalized uncertainty principle (GUP) modifications. In this work, within the framework of GUP gravity theory, we successfully derive an exact solution to Einstein’s field equation, and discuss the possibility of using EHT to test GUP and how GUP changes the weak cosmic censorship conjecture for black holes. We analyze two different ways of constructing GUP rotating black holes (model I and model II). Model I takes into account the modification of mass by GUP, i.e., the change in mass by quantization of space, and the resulting GUP rotating black hole metric (18) is similar in form to the Kerr black hole metric. Model II takes into account the modification of the rotating black hole when GUP is an external field, where GUP acts like an electric charge, and the resulting GUP rotating black hole metric (19) is similar in form to the Kerr–Newman black hole metric. The difference between (18) and (19) in the spacetime linear structure provides a basis for us to examine the physical nature of GUP rotating black holes from observation. By analyzing the shadow shape of the GUP rotating black hole, we discover intriguing characteristics regarding the impact of first-order and second-order momentum correction coefficients on the black hole’s shadow shape. These findings will be instrumental in future GUP testing using EHT. Additionally, by incident test particle and scalar field with a rotating GUP black hole, the weak cosmic censorship conjecture is not violated in either extreme black holes or near-extreme black holes.

Classical and Quantised Resolvent Algebras for the Cylinder

AbstractBuchholz and Grundling (Commun Math Phys 272:699–750, 2007) introduced a $$\hbox {C}^*$$ C ∗ -algebra called the resolvent algebra as a canonical quantisation of a symplectic vector space and demonstrated that this algebra has several desirable features. We define an analogue of their resolvent algebra on the cotangent bundle $$T^*\mathbb {T}^n$$ T ∗ T n of an n-torus by first generalising the classical analogue of the resolvent algebra defined by the first author of this paper in earlier work (van Nuland in J Funct Anal 277:2815–2838, 2019) and subsequently applying Weyl quantisation. We prove that this quantisation is almost strict in the sense of Rieffel and show that our resolvent algebra shares many features with the original resolvent algebra. We demonstrate that both our classical and quantised algebras are closed under the time evolutions corresponding to large classes of potentials. Finally, we discuss their relevance to lattice gauge theory.

Primordial Black Holes from Spatially Varying Cosmological Constant Induced by Field Fluctuations in Extra Dimensions

The origin and evolution of supermassive black holes (SMBHs) in our universe have sparked controversy. In this study, we explore the hypothesis that some of these black holes may have seeded from the direct collapse of dark energy domains with density significantly higher than the surrounding regions. The mechanism of the origin of such domains relies on the inflationary evolution of a scalar field acting in D dimensions, which is associated with the cosmological constant in our four-dimensional spacetime manifold. Inner space quantum fluctuations of the field during inflation are responsible for the spatial variations of the dark energy density in our space. This finding holds particular significance, especially considering recent evidence from pulsar timing array observations, which supports the existence of a stochastic gravitational wave background consisting of SMBH mergers.

Expand-and-Quantize: Unsupervised Semantic Segmentation Using High-Dimensional Space and Product Quantization

Unsupervised semantic segmentation (USS) aims to discover and recognize meaningful categories without any labels. For a successful USS, two key abilities are required: 1) information compression and 2) clustering capability. Previous methods have relied on feature dimension reduction for information compression, however, this approach may hinder the process of clustering. In this paper, we propose a novel USS framework called Expand-and-Quantize Unsupervised Semantic Segmentation (EQUSS), which combines the benefits of high-dimensional spaces for better clustering and product quantization for effective information compression. Our extensive experiments demonstrate that EQUSS achieves state-of-the-art results on three standard benchmarks. In addition, we analyze the entropy of USS features, which is the first step towards understanding USS from the perspective of information theory.

Study on the relation between interface trap creation and MOSFET degradation under channel hot carrier stressing at cryogenic temperatures

In general, the degradation mechanism of MOSFETs has been discussed relating to hydrogen. For instance, interface traps are created due to the Si–H bond breakage at the MOS interface by hot (energetic) carriers under electrical stressing (e.g. channel hot carrier (CHC) and F-N stressing). In addition, it is also reported that hydrogen also relates to bulk trap creation. However, these hydrogen-related degradation mechanisms have been discussed based on the results within the conventional measurement temperature region. Recently, the reliabilities of MOSFETs at cryogenic temperatures have attracted much attention assuming that the electron devices are applied to quantum computing and space exploration. However, degradation mechanisms at cryogenic temperatures have yet to be fully clarified. In this paper, the degradations of MOSFETs under a CHC stressing in the temperature range of 77 K ∼ 300 K are investigated. Especially, we focus on the degradation of MOSFETs due to interface trap creation. As a result, MOSFETs degrade more under cryogenic temperature compared to that near RT. This result implies the existence of an additional degradation mechanism at cryogenic temperatures.

Time transfer over 113 km free space laser communication channel.

The space time frequency transfer plays a crucial role in applications such as space optical clock networks, navigation, satellite ranging, and space quantum communication. Here, we propose a high-precision space time frequency transfer and time synchronization scheme based on a simple intensity modulation/direct detection (IM/DD) laser communication system, which occupies a communication bandwidth of approximately 0.2%. Furthermore, utilizing an optical-frequency comb time frequency transfer system as an out-of-loop reference, experimental verification was conducted on a 113 km horizontal atmospheric link, with a long-term stability approximately 8.3 × 10-16 over a duration of 7800 seconds. Over an 11-hour period, the peak-to-peak wander is approximately 100 ps. Our work establishes the foundation of the time frequency transfer, based on the space laser communication channel, for future ground-to-space and inter-satellite links.

Quantum Propulsion: Background and Practical Applications

This is the first introduction of new and revolutionary aerospace engines and propulsion methods. Our organization is currently developing quantum propulsion systems and space vehicles that will be capable of flying with enormous speed (potentially reaching and exceeding the speed of light) and will have unseen-before manoeuvrability and lifting capacity. They will provide 100% crew protection from deadly sun and space radiation which is essential for safe deep space travel and manned space exploration. They will also provide spacecraft with protection against space particles. To date, we have managed to crack the main secret of practical quantum engine design and we are ready to develop it further into fully operational aerospace vehicles. Quantum propulsion systems are the only systems that can facilitate realistic prospects of space mining on the industrial scale and deep space colonisation, including colonisation of habitable planets in the future. The cost efficiency of this new technology is going to be enormous. Development and production costs of quantum aerospace vehicles compared to production costs of chemical fuel jet spacecraft allow to reduce price per kilo space launch ratio hundreds of times, making deep space exploration and commercialisation more accessible and practically feasible at last. Manufacturing and maintenance of quantum-propelled flying machines that can reach the age of our solar system within hours will be no more expensive than manufacturing jet planes or helicopters of the same size. Quantum propulsion systems are going to replace outdated chemical fuel rocket and jet engines in the near future and will become the mainstay of air travel and space exploration.

PRINCIPLES OF ORGANIZATION OF THE MATERIAL WORLD

An attempt has been made to present and describe the PRINCIPLES OF ORGANIZATION OF THE MATERIAL WORLD using the “Scheme of the structure of our world”, which is the foundation of the philosophy of Hermeticism. In it, the three parts of the philosophy of the Universe are designated as the three Kingdoms that make up our world - Abstractions, Mass and Gravity, as well as Radiation. A diagram is shown for converting time into mass and back to implement phase transitions of matter into various states in the series: radiation – free space – dark matter – baryonic matter – black holes. The Scheme points to the location of dark energy. The geometric body of the rank space and the fractal principle of its construction are demonstrated. The previously proposed concepts were repeated: a) material zero as an elementary/electromagnetic quantum of space EQS; b) space-time complex of STC inside the quantum of space; c) the axis of the speed of time as an indicator for phase transitions of space quanta.

Four-state continuous variable quantum key distribution with two accelerating partners

The field of quantum communication has gradually expanded to include satellites in Earth's orbit. However, for long-distance communication protocols, gravity and its effect on quantum states must be taken into account. By applying the equivalence principle, we can consider that the gravitational effects are equivalent to the acceleration that observers possess. A comprehensive method is proposed to find out the effect of gravity on the performance of the four-state continuous-variable quantum key distribution (CV-QKD) protocol. Finally, the effects of gravity on the QKD of each protocol are discussed, and the associated factors are also analyzed. The performance of the CV-QKD protocol under the effects of gravity is deeply analyzed by taking acceleration into consideration. Both the asymptotic key rate and the finite-size key rate are analyzed in this paper. Furthermore, significant room exists for improving the security and efficiency of space quantum communication.

Quantum de Sitter Geometry

Quantum de Sitter geometry is discussed using elementary field operator algebras in Krein space quantization from an observer-independent point of view, i.e., ambient space formalism. In quantum geometry, the conformal sector of the metric becomes a dynamical degree of freedom, which can be written in terms of a massless minimally coupled scalar field. The elementary fields necessary for the construction of quantum geometry are introduced and classified. A complete Krein–Fock space structure for elementary fields is presented using field operator algebras. We conclude that since quantum de Sitter geometry can be constructed by elementary fields operators, the geometry quantum state is immersed in the Krein–Fock space and evolves in it. The total number of accessible quantum states in the universe is chosen as a parameter of quantum state evolution, which has a relationship with the universe’s entropy. Inspired by the Wheeler–DeWitt constraint equation in cosmology, the evolution equation of the geometry quantum state is formulated in terms of the Lagrangian density of interaction fields in ambient space formalism.

Voltage-controlled cryogenic Boolean logic gates based on ferroelectric SQUID and heater cryotron

The recent progress in quantum computing and space exploration led to a surge in interest in cryogenic electronics. Superconducting devices such as Josephson junction, Josephson field effect transistor, cryotron, and superconducting quantum interference device (SQUID) are traditionally used to build cryogenic logic gates. However, due to the superconducting nature, gate-voltage-based control of these devices is extremely difficult. Even more challenging is to cascade the logic gates because most of these devices require current bias for their operation. Therefore, these devices are not as convenient as the semiconducting transistors to design logic gates. Here, to overcome these challenges, we propose a ferroelectric SQUID (FeSQUID) based voltage-controlled logic gates. FeSQUID exhibits two different critical current levels for two different voltage-switchable polarization states of the ferroelectric. We utilize the polarization-dependent (hence, voltage-controllable) superconducting to resistive switching of FeSQUID to design Boolean logic gates such as Copy, NOT, AND, and OR gates. The operations of these gates are verified using a Verilog-A-based compact model of FeSQUID. Finally, to demonstrate the fanning out capability of FeSQUID-based logic family, we simulate a two-input XOR gate using FeSQUID-based NOT, AND, and OR gates. Together with the ongoing progress on FeSQUID-based non-volatile memory, our designed FeSQUID-based logic family will enable all FeSQUID-based cryogenic computer, ensuring minimum mismatch between logic and memory blocks in terms of speed, power consumption, and fabrication process.

Radiation effect on silicon photonics chips for space quantum key distribution.

Quantum communication satellites have potential for applications in future quantum networks. Photonics integrated chips, due to their compact and lightweight nature, are well-suited for satellite deployment. However, the harsh radiation environment of space can cause permanent damage to these chips, resulting in degraded performance or complete loss of functionality. In this work, we conducted a series of radiation experiments to evaluate the effects of γ rays and high energy protons on quantum key distribution transmitter chips. The results suggest that the insertion loss of the chip is slightly reduced by about 1.5 dB after 100 krad (Si) γ ray irradiation, and further reduced by about 0.5 to 1 dB after 2.39 × 1011/cm2 proton radiation. The half-wave voltages, extinction ratios, and polarization angles are not changed significantly within the measurement error range. Our work proves the feasibility of deploying quantum constellations utilizing terminals based on photonics chips.

Gravitation, Density Upper Limit and Quantization of Space

Gravitation, Density Upper Limit and Quantization of Space

Theory of Space Quantization (Tsq) Driven Version of the Conventional Theories of Physics, Relativity and Gravitation-A Concise Report

The global scientific community at the moment is awaiting passionately for a ‘Theory of Everything’ (TOE) and the level of expectation of the said community is, i) the Theory has to be very robust and versatile ii) the theory should be in a position to fully explain and connect all the happenings and aspects of the universe and iii) the said TOE has to be a multi block compatibilizing one (is in harmony with the existing theories of physics) and as well has to establish the fact that the theories of physics proposed so far, though have been presented in many different forms but they are inherently being identical by their origins or routes. In this small article it is being reported that the recently discovered ‘ Topological Theory of Quantum gravity (TTQG) or the ‘ Theory of Space Quantization’ (TSQ) has already unified the theories of ‘Newtonian physics or classical physics’, ‘thermodynamics’, ‘quantum mechanics’, ‘cosmological theories’ and the ‘theories of relativities’ under a single umbrella and revealed the dimensionalities of ‘time’ , ‘mass’, ‘space expansion-space inversion’ of the universe , geometries of ‘gravitation’ the ‘singularity’ and the dimensionality of the universe itself and as well presented an ‘Universal Graviton Cycle’ to explain most of the cosmic/astronomical phenomena of the universe in a single frame. It is a first foot step of TSQ or TTQG to ultimately converge to the ‘Theory of Everything’.

On Another Type of Convergence for Intuitionistic Fuzzy Observables

The convergence theorems play an important role in the theory of probability and statistics and in its application. In recent times, we studied three types of convergence of intuitionistic fuzzy observables, i.e., convergence in distribution, convergence in measure and almost everywhere convergence. In connection with this, some limit theorems, such as the central limit theorem, the weak law of large numbers, the Fisher–Tippet–Gnedenko theorem, the strong law of large numbers and its modification, have been proved. In 1997, B. Riečan studied an almost uniform convergence on D-posets, and he showed the connection between almost everywhere convergence in the Kolmogorov probability space and almost uniform convergence in D-posets. In 1999, M. Jurečková followed on from his research, and she proved the Egorov’s theorem for observables in MV-algebra using results from D-posets. Later, in 2017, the authors R. Bartková, B. Riečan and A. Tirpáková studied an almost uniform convergence and the Egorov’s theorem for fuzzy observables in the fuzzy quantum space. As the intuitionistic fuzzy sets introduced by K. T. Atanassov are an extension of the fuzzy sets introduced by L. Zadeh, it is interesting to study an almost uniform convergence on the family of the intuitionistic fuzzy sets. The aim of this contribution is to define an almost uniform convergence for intuitionistic fuzzy observables. We show the connection between the almost everywhere convergence and almost uniform convergence of a sequence of intuitionistic fuzzy observables, and we formulate a version of Egorov’s theorem for the case of intuitionistic fuzzy observables. We use the embedding of the intuitionistic fuzzy space into the suitable MV-algebra introduced by B. Riečan. We formulate the connection between the almost uniform convergence of functions of several intuitionistic fuzzy observables and almost uniform convergence of random variables in the Kolmogorov probability space too.

The continuity equation in the phase space quantum mechanics

A quantum phase space version of the continuity equation for systems with internal degrees of freedom is derived. The 1-D Dirac equation is introduced and its phase space counterpart is found. The phase space representation of free motion and of scattering in a nonrelativistic and relativistic case for setups with internal degrees of freedom is discussed and illustrated. Properties of Wigner functions of unbound states are analysed.

Controlled quantum teleportation with the ability to change the destination of qubits

Quantum sciences and technologies introduce a new arena whose applications are widely used in the microscopic world. Quantum communication is also an important branch of quantum science by which we intend to transmit quantum information. Quantum teleportation is important because it uses the entanglement principle which is unique in quantum space to transmit quantum information. In fact, in this type of protocol, no information is sent and everything is transmitted using the miracle of entanglement. In this paper, an attempt is made to present a quantum teleportation scheme that, unlike the other designs, can change the destination of qubits. This means that at the beginning of the protocol, the receivers have no idea who has sent the qubits, and the controller decides how these communications will work. At last, noise analysis is presented.

Quantization of spherically symmetric loop quantum gravity coupled to a scalar field and a clock: the asymptotic limit

We continue our work on the study of spherically symmetric loop quantum gravity coupled to two spherically symmetric scalar fields, one which acts as a clock. As a consequence of the presence of the latter, we can define a true Hamiltonian for the theory. The spherically symmetric context allows to carry out precise detailed calculations. Here we study the theory for regions of large values of the radial coordinate. This allows us to define in detail the vacuum of the theory and study its quantum states, yielding a quantum field theory on a quantum space time that makes contact with the usual treatment on classical space times.

Мethod for determining the level of similarity of images by color component based on correlation analysis and color space quantization

The color component of an image is the basic information about the image. Color determines the mood of an image, its concept, and can also serve as a semantic accent. Obtaining information about the color component of an image is necessary when solving various kinds of tasks. For example, the task of finding similar images according to the content, as information about the color component can be combined with other metadata of the image and more fully describe its concept. In this paper authors describe the physical representation of color, the most popular digital representations of color, ways of extracting color components of an image, such as color histograms, quantization, coherent vectors and K -means, and ways of comparing color components of images, such as Euclidean distance, cosine distance, Manhattan distance, Chebyshev distance, Jaccard index, correlation analysis, Pearson's agreement test and Bhattacharya distance. It is suggested that the use of histogram comparison and vector comparison methods is acceptable for comparing the color components of images, since color histograms can be written in vector form. The authors conduct an experiment in which a human expert reviews combinations of color component acquisition and comparison methods and completes a test protocol based on the criteria highlighted by the authors. The criteria were based on the human interpretability of the results of the methods of determining and comparing the color component. On the basis of the experiment it has been determined that the best of the methods of comparison of color components of the definition images considered in the article is the correlation analysis of color histograms of images, which have been extracted in a quantized color space, because this approach meets all the criteria for testing and keeps the greatest amount of information about the color component.