Pub Date : 2023-05-25DOI: 10.1088/2399-6528/acd90e
L. Rincón, L. Seijas, R. Almeida, F. Javier Torres
One of the primary obstacles in the development of orbital–free density functional theory is the lack of an accurate functional for the Kohn–Sham non-interacting kinetic energy, which, in addition to its accuracy, must also render a good approximation for its functional derivative. To address this critical issue, we propose the construction of a kinetic energy density functional throught physical- informed neural network, where the neural network’s loss function is designed to simultaneously reproduce the atom’s shell structures, and also, an analytically calculated functional derivative. As a proof-of-concept, we have tested the accuracy of the kinetic energy potential by optimizing electron densities for atoms from Li to Xe.
{"title":"Towards the construction of an accurate kinetic energy density functional and its functional derivative through physics-informed neural networks","authors":"L. Rincón, L. Seijas, R. Almeida, F. Javier Torres","doi":"10.1088/2399-6528/acd90e","DOIUrl":"https://doi.org/10.1088/2399-6528/acd90e","url":null,"abstract":"One of the primary obstacles in the development of orbital–free density functional theory is the lack of an accurate functional for the Kohn–Sham non-interacting kinetic energy, which, in addition to its accuracy, must also render a good approximation for its functional derivative. To address this critical issue, we propose the construction of a kinetic energy density functional throught physical- informed neural network, where the neural network’s loss function is designed to simultaneously reproduce the atom’s shell structures, and also, an analytically calculated functional derivative. As a proof-of-concept, we have tested the accuracy of the kinetic energy potential by optimizing electron densities for atoms from Li to Xe.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41960917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-19DOI: 10.1088/2399-6528/acd746
W. Luhs, B. Wellegehausen
Investigations on 405 nm diode-pumped cw ruby lasers operated in less than 3 mm plane-parallel resonators are reported. With 2.5 mm long ruby crystals TEM00 emission with output powers up to 40 mW are achieved. With an uncoated thin etalon of 0.13 mm thickness, single frequency emission on both ruby lines R1 and R2 is possible. With the piezoelectric shifting of one resonator mirror and corresponding tilting of the etalon, single frequency tuning of up to 400 GHz has been achieved. Details of the laser system are presented, and potential applications will be discussed.
{"title":"Diode pumped compact single frequency cw ruby laser","authors":"W. Luhs, B. Wellegehausen","doi":"10.1088/2399-6528/acd746","DOIUrl":"https://doi.org/10.1088/2399-6528/acd746","url":null,"abstract":"Investigations on 405 nm diode-pumped cw ruby lasers operated in less than 3 mm plane-parallel resonators are reported. With 2.5 mm long ruby crystals TEM00 emission with output powers up to 40 mW are achieved. With an uncoated thin etalon of 0.13 mm thickness, single frequency emission on both ruby lines R1 and R2 is possible. With the piezoelectric shifting of one resonator mirror and corresponding tilting of the etalon, single frequency tuning of up to 400 GHz has been achieved. Details of the laser system are presented, and potential applications will be discussed.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47405027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-19DOI: 10.1088/2399-6528/acd748
R. Rajan, S. Ramesh, S. B. Boppana, P. Krishnan
In this study, four different combinations of aluminium metal matrix composites (AMCs) were produced using a computerized stir casting process. The feasibility of using car Scrap Aluminium Engine Head (SAEH) as matrix material, Fresh Alumina Catalyst (FAC) and Spent Alumina Catalyst (SAC) from petrochemical industries as reinforcement material were investigated. The physical and mechanical properties of the cast samples were tested through density, hardness, tensile, compression, and impact test. Microstructural investigations were carried out using an optical microscope, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Differential thermal analysis (DTA) and Thermo gravimetric analysis (TGA) were also conducted to justify the results obtained. The results indicated that SAEH reinforced with 5 wt% SAC exhibited lower porosity (2.6%) and higher Brinell hardness (71.5 BHN), Vickers hardness (307.1 VHN), tensile strength (217 MPa), and compressive strength (426 MPa) than other composites. Additionally, this composite showed the highest impact strength (0.02375 J mm−2) and DTA value (568.5 μV mg−1). The TGA result showed that all composites had high thermal stability, with the SAC-reinforced composites having the highest thermal stability (100.13%).
{"title":"Sustainable development on production and characterization of metal matrix composites using stir casting","authors":"R. Rajan, S. Ramesh, S. B. Boppana, P. Krishnan","doi":"10.1088/2399-6528/acd748","DOIUrl":"https://doi.org/10.1088/2399-6528/acd748","url":null,"abstract":"In this study, four different combinations of aluminium metal matrix composites (AMCs) were produced using a computerized stir casting process. The feasibility of using car Scrap Aluminium Engine Head (SAEH) as matrix material, Fresh Alumina Catalyst (FAC) and Spent Alumina Catalyst (SAC) from petrochemical industries as reinforcement material were investigated. The physical and mechanical properties of the cast samples were tested through density, hardness, tensile, compression, and impact test. Microstructural investigations were carried out using an optical microscope, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Differential thermal analysis (DTA) and Thermo gravimetric analysis (TGA) were also conducted to justify the results obtained. The results indicated that SAEH reinforced with 5 wt% SAC exhibited lower porosity (2.6%) and higher Brinell hardness (71.5 BHN), Vickers hardness (307.1 VHN), tensile strength (217 MPa), and compressive strength (426 MPa) than other composites. Additionally, this composite showed the highest impact strength (0.02375 J mm−2) and DTA value (568.5 μV mg−1). The TGA result showed that all composites had high thermal stability, with the SAC-reinforced composites having the highest thermal stability (100.13%).","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45975203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-12DOI: 10.1088/2399-6528/acd51d
J. Kumlin, C. Braun, C. Tresp, N. Stiesdal, S. Hofferberth, A. Paris-Mandoki
Quantum optics based on highly excited atoms, also known as Rydberg atoms, has cemented itself as a powerful platform for the manipulation of light at the few-photon level. The Rydberg blockade, resulting from the strong interaction between individual Rydberg atoms, can turn a large ensemble of atoms into a system which collectively resembles a single two-level emitter, a so-called Rydberg superatom. The coupling of this artificial emitter to a driving photonic mode is collectively enhanced by Rydberg interactions, enabling strong coherent coupling at the few-photon level in free-space. The exquisite level of control achievable through this has already demonstrated its utility in applications of quantum computing and information processing. Here, we review the derivation of the collective coupling between a Rydberg superatom and a single light mode and discuss the similarity of this free-space setup to waveguide quantum electrodynamics systems of quantum emitters coupled to photonic waveguides. We also briefly review applications of Rydberg superatoms to quantum optics such as single-photon generation and single-photon subtraction.
{"title":"Quantum optics with Rydberg superatoms","authors":"J. Kumlin, C. Braun, C. Tresp, N. Stiesdal, S. Hofferberth, A. Paris-Mandoki","doi":"10.1088/2399-6528/acd51d","DOIUrl":"https://doi.org/10.1088/2399-6528/acd51d","url":null,"abstract":"Quantum optics based on highly excited atoms, also known as Rydberg atoms, has cemented itself as a powerful platform for the manipulation of light at the few-photon level. The Rydberg blockade, resulting from the strong interaction between individual Rydberg atoms, can turn a large ensemble of atoms into a system which collectively resembles a single two-level emitter, a so-called Rydberg superatom. The coupling of this artificial emitter to a driving photonic mode is collectively enhanced by Rydberg interactions, enabling strong coherent coupling at the few-photon level in free-space. The exquisite level of control achievable through this has already demonstrated its utility in applications of quantum computing and information processing. Here, we review the derivation of the collective coupling between a Rydberg superatom and a single light mode and discuss the similarity of this free-space setup to waveguide quantum electrodynamics systems of quantum emitters coupled to photonic waveguides. We also briefly review applications of Rydberg superatoms to quantum optics such as single-photon generation and single-photon subtraction.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41619942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-05DOI: 10.1088/2399-6528/acd320
Shoji Yamamoto, J. Ohara
We propose a new scheme of modifying spin waves so as to describe the thermodynamic properties of various noncollinear antiferromagnets with particular interest in a comparison between edge- versus corner-sharing triangular-based lattices. The well-known modified spin-wave theory for collinear antiferromagnets diagonalizes a bosonic Hamiltonian subject to the constraint that the total staggered magnetization be zero. Applying this scheme to frustrated noncollinear antiferromagnets ends in a poor thermodynamics, missing the optimal ground state and breaking the local U(1) rotational symmetry. We find such a plausible double-constraint condition for spin spirals as to spontaneously go back to the traditional single-constraint condition at the onset of a collinear Néel-ordered classical ground state. We first diagonalize only the bilinear terms in Holstein-Primakoff boson operators on the order of spin magnitude S and then bring these linear spin waves into interaction in a perturbative rather than variational manner. We demonstrate specific-heat calculations in terms of thus-modified interacting spin waves on various triangular-based lattices. In zero dimension, modified-spin-wave findings in comparison with finite-temperature Lanczos calculations turn out so successful as to reproduce the monomodal and bimodal specific-heat temperature profiles of the triangular-based edge-sharing Platonic and corner-sharing Archimedean polyhedral-lattice antiferromagnets, respectively. In two dimensions, high-temperature series expansions and tensor-network-based renormalization-group calculations are still controversial especially at low temperatures, and under such circumstances, modified spin waves interestingly predict that the specific heat of the kagome-lattice antiferromagnet in the corner-sharing geometry remains having both mid-temperature broad maximum and low-temperature narrow peak in the thermodynamic limit, while the specific heat of the triangular-lattice antiferromagnet in the edge-sharing geometry retains a low-temperature sharp peak followed by a mid-temperature weak anormaly in the thermodynamic limit. By further calculating one-magnon spectral functions in terms of our newly developed double-constraint modified spin-wave theory, we reveal that not only the elaborate modification scheme but also quantum corrections, especially those caused by the O(S 0) primary self-energies, are key ingredients in the successful description of triangular-based-lattice noncollinear antiferromagnets over the whole temperature range of absolute zero to infinity.
{"title":"Thermal features of Heisenberg antiferromagnets on edge- versus corner-sharing triangular-based lattices: a message from spin waves","authors":"Shoji Yamamoto, J. Ohara","doi":"10.1088/2399-6528/acd320","DOIUrl":"https://doi.org/10.1088/2399-6528/acd320","url":null,"abstract":"We propose a new scheme of modifying spin waves so as to describe the thermodynamic properties of various noncollinear antiferromagnets with particular interest in a comparison between edge- versus corner-sharing triangular-based lattices. The well-known modified spin-wave theory for collinear antiferromagnets diagonalizes a bosonic Hamiltonian subject to the constraint that the total staggered magnetization be zero. Applying this scheme to frustrated noncollinear antiferromagnets ends in a poor thermodynamics, missing the optimal ground state and breaking the local U(1) rotational symmetry. We find such a plausible double-constraint condition for spin spirals as to spontaneously go back to the traditional single-constraint condition at the onset of a collinear Néel-ordered classical ground state. We first diagonalize only the bilinear terms in Holstein-Primakoff boson operators on the order of spin magnitude S and then bring these linear spin waves into interaction in a perturbative rather than variational manner. We demonstrate specific-heat calculations in terms of thus-modified interacting spin waves on various triangular-based lattices. In zero dimension, modified-spin-wave findings in comparison with finite-temperature Lanczos calculations turn out so successful as to reproduce the monomodal and bimodal specific-heat temperature profiles of the triangular-based edge-sharing Platonic and corner-sharing Archimedean polyhedral-lattice antiferromagnets, respectively. In two dimensions, high-temperature series expansions and tensor-network-based renormalization-group calculations are still controversial especially at low temperatures, and under such circumstances, modified spin waves interestingly predict that the specific heat of the kagome-lattice antiferromagnet in the corner-sharing geometry remains having both mid-temperature broad maximum and low-temperature narrow peak in the thermodynamic limit, while the specific heat of the triangular-lattice antiferromagnet in the edge-sharing geometry retains a low-temperature sharp peak followed by a mid-temperature weak anormaly in the thermodynamic limit. By further calculating one-magnon spectral functions in terms of our newly developed double-constraint modified spin-wave theory, we reveal that not only the elaborate modification scheme but also quantum corrections, especially those caused by the O(S 0) primary self-energies, are key ingredients in the successful description of triangular-based-lattice noncollinear antiferromagnets over the whole temperature range of absolute zero to infinity.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42674244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.1088/2399-6528/acd2a4
Zoltán Udvarnoki, G. Fáth, N. Fogarasi
Quantum computers have the potential to provide quadratic speedup for Monte Carlo methods currently used in various classical applications. In this work, we examine the advantage of quantum computers for financial option pricing with the Monte Carlo method. Systematic and statistical errors are handled in a joint framework, and a relationship to quantum gate error is established. New metrics are introduced for the assessment of quantum advantage based on sample count and optimized error handling. We implement and analyze a Fourier series based approach and demonstrate its benefit over the more traditional rescaling method in function approximation. Our numerical calculations reveal the unpredictable nature of systematic errors, making consistent quantum advantage difficult with current quantum hardware. Our results indicate that very low noise levels, a two-qubit gate error rate below 10−6, are necessary for the quantum method to outperform the classical one, but a low number of logical qubits (ca. 20) may be sufficient to see quantum advantage already.
{"title":"Quantum advantage of Monte Carlo option pricing","authors":"Zoltán Udvarnoki, G. Fáth, N. Fogarasi","doi":"10.1088/2399-6528/acd2a4","DOIUrl":"https://doi.org/10.1088/2399-6528/acd2a4","url":null,"abstract":"Quantum computers have the potential to provide quadratic speedup for Monte Carlo methods currently used in various classical applications. In this work, we examine the advantage of quantum computers for financial option pricing with the Monte Carlo method. Systematic and statistical errors are handled in a joint framework, and a relationship to quantum gate error is established. New metrics are introduced for the assessment of quantum advantage based on sample count and optimized error handling. We implement and analyze a Fourier series based approach and demonstrate its benefit over the more traditional rescaling method in function approximation. Our numerical calculations reveal the unpredictable nature of systematic errors, making consistent quantum advantage difficult with current quantum hardware. Our results indicate that very low noise levels, a two-qubit gate error rate below 10−6, are necessary for the quantum method to outperform the classical one, but a low number of logical qubits (ca. 20) may be sufficient to see quantum advantage already.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48158410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.1088/2399-6528/acd167
I. Goode, C. Saavedra
3D printing technology has significant potential to modernize the student laboratory experience in the area of electromagnetic wave propagation and scattering. In this contribution, a fast and low-cost method to 3D print and metallize a variable aperture horn and waveguide launcher are presented. The launcher converts a SubMiniature version A (SMA) coaxial connector to WR 187 waveguide (standard size of waveguide for 3.95 GHz to 5.85 GHz) and is printed from plastic while being metallized with aluminum tape. The launcher provided similar performance to an off the shelf launcher at one 40th the cost. As a teachable extension to this launcher a variable aperture horn is 3D printed and metallized with aluminum tape. The aperture area of the horn is changed by rotating the E⃗ walls of the horn away from each other by use of pivot in the transition between the launcher and the horn. This horn showed the expected decrease in beamwidth and increase in peak gain as the aperture area was increased while maintaining a usable impedance match. Modular center ridges were also printed to demonstrate the utility of center ridges in a horn antenna without H⃗ walls. Overall, a modular, inexpensive, and easy to construct waveguide system is presented that is useful for teaching electromagnetics specifically the relationship between aperture area and antenna gain, as well as providing a platform for waveguide experiments.
{"title":"3D printed variable aperture horn with modular ridges","authors":"I. Goode, C. Saavedra","doi":"10.1088/2399-6528/acd167","DOIUrl":"https://doi.org/10.1088/2399-6528/acd167","url":null,"abstract":"3D printing technology has significant potential to modernize the student laboratory experience in the area of electromagnetic wave propagation and scattering. In this contribution, a fast and low-cost method to 3D print and metallize a variable aperture horn and waveguide launcher are presented. The launcher converts a SubMiniature version A (SMA) coaxial connector to WR 187 waveguide (standard size of waveguide for 3.95 GHz to 5.85 GHz) and is printed from plastic while being metallized with aluminum tape. The launcher provided similar performance to an off the shelf launcher at one 40th the cost. As a teachable extension to this launcher a variable aperture horn is 3D printed and metallized with aluminum tape. The aperture area of the horn is changed by rotating the E⃗ walls of the horn away from each other by use of pivot in the transition between the launcher and the horn. This horn showed the expected decrease in beamwidth and increase in peak gain as the aperture area was increased while maintaining a usable impedance match. Modular center ridges were also printed to demonstrate the utility of center ridges in a horn antenna without H⃗ walls. Overall, a modular, inexpensive, and easy to construct waveguide system is presented that is useful for teaching electromagnetics specifically the relationship between aperture area and antenna gain, as well as providing a platform for waveguide experiments.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48697280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.1088/2399-6528/acddcc
Joshua G. Fenwick, R. Dick
Imposing the Born rule as a fundamental principle of quantum mechanics would require the existence of normalizable wave functions ψ( x , t) also for relativistic particles. Indeed, the Fourier transforms of normalized k -space amplitudes ψ(k,t)=ψ(k)exp(−iωkt) yield normalized functions ψ( x , t) which reproduce the standard k -space expectation values for energy and momentum from local momentum (pseudo-)densities ℘ μ ( x , t) = (ℏ/2i)[ψ +( x , t)∂ μ ψ( x , t) − ∂ μ ψ +( x , t) · ψ( x , t)]. However, in the case of bosonic fields, the wave packets ψ( x , t) are nonlocally related to the corresponding relativistic quantum fields ϕ( x , t), and therefore the canonical local energy-momentum densities (x,t)=c0(x,t) and (x,t) differ from ℘ μ ( x , t) and appear nonlocal in terms of the wave packets ψ( x , t). We examine the relation between the canonical energy density (x,t) , the canonical charge density ϱ( x , t), the energy pseudo-density ˜(x,t)=c℘0(x,t) , and the Born density ∣ψ( x , t)∣2 for the massless free Klein–Gordon field. We find that those four proxies for particle location are tantalizingly close even in this extremely relativistic case: in spite of their nonlocal mathematical relations, they are mutually local in the sense that their maxima do not deviate beyond a common position uncertainty Δx. Indeed, they are practically indistinguishable in cases where we would expect a normalized quantum state to produce particle-like position signals, viz. if we are observing quanta with momenta p ≫ Δp ≥ ℏ/2Δx. We also translate our results to massless Dirac fields. Our results confirm and illustrate that the normalized energy density (x,t)/E provides a suitable measure for positions of bosons, whereas normalized charge density ϱ( x , t)/q provides a suitable measure for fermions.
{"title":"Relativistic probability densities for location","authors":"Joshua G. Fenwick, R. Dick","doi":"10.1088/2399-6528/acddcc","DOIUrl":"https://doi.org/10.1088/2399-6528/acddcc","url":null,"abstract":"Imposing the Born rule as a fundamental principle of quantum mechanics would require the existence of normalizable wave functions ψ( x , t) also for relativistic particles. Indeed, the Fourier transforms of normalized k -space amplitudes ψ(k,t)=ψ(k)exp(−iωkt) yield normalized functions ψ( x , t) which reproduce the standard k -space expectation values for energy and momentum from local momentum (pseudo-)densities ℘ μ ( x , t) = (ℏ/2i)[ψ +( x , t)∂ μ ψ( x , t) − ∂ μ ψ +( x , t) · ψ( x , t)]. However, in the case of bosonic fields, the wave packets ψ( x , t) are nonlocally related to the corresponding relativistic quantum fields ϕ( x , t), and therefore the canonical local energy-momentum densities (x,t)=c0(x,t) and (x,t) differ from ℘ μ ( x , t) and appear nonlocal in terms of the wave packets ψ( x , t). We examine the relation between the canonical energy density (x,t) , the canonical charge density ϱ( x , t), the energy pseudo-density ˜(x,t)=c℘0(x,t) , and the Born density ∣ψ( x , t)∣2 for the massless free Klein–Gordon field. We find that those four proxies for particle location are tantalizingly close even in this extremely relativistic case: in spite of their nonlocal mathematical relations, they are mutually local in the sense that their maxima do not deviate beyond a common position uncertainty Δx. Indeed, they are practically indistinguishable in cases where we would expect a normalized quantum state to produce particle-like position signals, viz. if we are observing quanta with momenta p ≫ Δp ≥ ℏ/2Δx. We also translate our results to massless Dirac fields. Our results confirm and illustrate that the normalized energy density (x,t)/E provides a suitable measure for positions of bosons, whereas normalized charge density ϱ( x , t)/q provides a suitable measure for fermions.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48163455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.1088/2399-6528/accdb4
Saqer M Darwish
This theoretical work investigates spin-spin energy in the hydrogen atom and its relation to Coulomb’s force law. Most elementary particles are assigned intrinsic properties of carrying electric charges, which leave us blundering about the essence of electric charge. The perplexity originated in Coulomb’s force law when the proportionality constant is expressed using the free vacuum electric permittivity constant ε 0 in units of. C2m−2. N−1. Introducing these units by the proportionality constant canceled any direct role for the electric charge. In this research, a genuine suggestion based on energy conservation redefines Coulomb’s force law. A new formula has been suggested for the force between two spinning particles. The results of energy and force calculations agreed with Coulomb’s law evaluations. The spin-spin energy is related to the electric potential energy, and the electric charge is found to be connected to the rotational energy of the mass.
{"title":"Investigation of Coulomb’s law and the nature of the electric charge","authors":"Saqer M Darwish","doi":"10.1088/2399-6528/accdb4","DOIUrl":"https://doi.org/10.1088/2399-6528/accdb4","url":null,"abstract":"This theoretical work investigates spin-spin energy in the hydrogen atom and its relation to Coulomb’s force law. Most elementary particles are assigned intrinsic properties of carrying electric charges, which leave us blundering about the essence of electric charge. The perplexity originated in Coulomb’s force law when the proportionality constant is expressed using the free vacuum electric permittivity constant ε 0 in units of. C2m−2. N−1. Introducing these units by the proportionality constant canceled any direct role for the electric charge. In this research, a genuine suggestion based on energy conservation redefines Coulomb’s force law. A new formula has been suggested for the force between two spinning particles. The results of energy and force calculations agreed with Coulomb’s law evaluations. The spin-spin energy is related to the electric potential energy, and the electric charge is found to be connected to the rotational energy of the mass.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44879030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-13DOI: 10.1088/2399-6528/acce20
O. Olendski
Motion along semi-infinite straight line in a potential that is a combination of positive quadratic and inverse quadratic functions of the position is considered with the emphasis on the analysis of its quantum-information properties. Classical measure of symmetry of the potential is proposed and its dependence on the particle energy and the factor a describing a relative strength of its constituents is described; in particular, it is shown that a variation of the parameter a alters the shape from the half-harmonic oscillator (HHO) at a=0 to the perfectly symmetric one of the double frequency oscillator (DFO) in the limit of huge a . Quantum consideration focuses on the analysis of information-theoretical measures, such as standard deviations, Shannon, Rényi and Tsallis entropies together with Fisher information, Onicescu energy and non–Gaussianity. For doing this, among others, a method of calculating momentum waveforms is proposed that results in their analytic expressions in form of the confluent hypergeometric functions. Increasing parameter a modifies the measures in such a way that they gradually transform into those corresponding to the DFO what, in particular, means that the lowest orbital saturates Heisenberg, Shannon, Rényi and Tsallis uncertainty relations with the corresponding position and momentum non–Gaussianities turning to zero. A simple expression is derived of the orbital-independent lower threshold of the semi-infinite range of the dimensionless Rényi/Tsallis coefficient where momentum components of these one-parameter entropies exist which shows that it varies between 1/4 at HHO and zero when a tends to infinity. Physical interpretation of obtained mathematical results is provided.
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