Pub Date : 2022-12-20DOI: 10.1088/2399-6528/acad63
A. Speliotopoulos
The generalized Lie symmetries of almost regular Lagrangians are studied, and their impact on the evolution of dynamical systems is determined. It is found that if the action has a generalized Lie symmetry, then the Lagrangian is necessarily singular; the converse is not true, as we show with a specific example. It is also found that the generalized Lie symmetry of the action is a Lie subgroup of the generalized Lie symmetry of the Euler–Lagrange equations of motion. The converse is once again not true, and there are systems for which the Euler–Lagrange equations of motion have a generalized Lie symmetry while the action does not, as we once again show through a specific example. Most importantly, it is shown that each generalized Lie symmetry of the action contributes one arbitrary function to the evolution of the dynamical system. The number of such symmetries gives a lower bound to the dimensionality of the family of curves emanating from any set of allowed initial data in the Lagrangian phase space. Moreover, if second- or higher-order Lagrangian constraints are introduced during the application of the Lagrangian constraint algorithm, these additional constraints could not have been due to the generalized Lie symmetry of the action.
{"title":"Generalized Lie symmetries and almost regular Lagrangians: a link between symmetry and dynamics","authors":"A. Speliotopoulos","doi":"10.1088/2399-6528/acad63","DOIUrl":"https://doi.org/10.1088/2399-6528/acad63","url":null,"abstract":"The generalized Lie symmetries of almost regular Lagrangians are studied, and their impact on the evolution of dynamical systems is determined. It is found that if the action has a generalized Lie symmetry, then the Lagrangian is necessarily singular; the converse is not true, as we show with a specific example. It is also found that the generalized Lie symmetry of the action is a Lie subgroup of the generalized Lie symmetry of the Euler–Lagrange equations of motion. The converse is once again not true, and there are systems for which the Euler–Lagrange equations of motion have a generalized Lie symmetry while the action does not, as we once again show through a specific example. Most importantly, it is shown that each generalized Lie symmetry of the action contributes one arbitrary function to the evolution of the dynamical system. The number of such symmetries gives a lower bound to the dimensionality of the family of curves emanating from any set of allowed initial data in the Lagrangian phase space. Moreover, if second- or higher-order Lagrangian constraints are introduced during the application of the Lagrangian constraint algorithm, these additional constraints could not have been due to the generalized Lie symmetry of the action.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43264393","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 : 2022-12-19DOI: 10.1088/2399-6528/acac6e
A. Müller, M. Maiwald, B. Sumpf
785 nm micro-integrated, dual-wavelength master oscillator power amplifiers with a footprint of 5 mm × 25 mm are presented. They are based on Y-branch distributed Bragg reflector ridge waveguide diode lasers and anti-reflection coated tapered amplifiers. In order to reduce the impact of potential optical feedback, devices with master oscillator front facet reflectivities of 5% and 30% as well as with an integrated miniaturized optical isolator have been realized. A comparison up to 1 W shows narrowband dual wavelength laser emission with a spectral distance of 0.6 nm (10 cm−1) and individual spectral widths <20 pm. As expected, a higher front facet reflectivity leads to a significant reduction of feedback related mode hops. Longitudinal modes corresponding to the master oscillator resonator length remain within spectral windows <0.15 nm (3 cm−1), suitable for applications such as Raman spectroscopy and especially shifted excitation Raman difference spectroscopy. Integrating a compact 30 dB optical isolator completely eliminates the observed optical feedback effects. Lateral beam propagation ratios of 1.2 (1/e2) enable easy beam shaping and fiber coupling. Outside of the experimental comparison, the developed MOPAs provide up to 2.7 W of optical output power available for applications.
{"title":"Compact, Watt-class 785 nm dual-wavelength master oscillator power amplifiers","authors":"A. Müller, M. Maiwald, B. Sumpf","doi":"10.1088/2399-6528/acac6e","DOIUrl":"https://doi.org/10.1088/2399-6528/acac6e","url":null,"abstract":"785 nm micro-integrated, dual-wavelength master oscillator power amplifiers with a footprint of 5 mm × 25 mm are presented. They are based on Y-branch distributed Bragg reflector ridge waveguide diode lasers and anti-reflection coated tapered amplifiers. In order to reduce the impact of potential optical feedback, devices with master oscillator front facet reflectivities of 5% and 30% as well as with an integrated miniaturized optical isolator have been realized. A comparison up to 1 W shows narrowband dual wavelength laser emission with a spectral distance of 0.6 nm (10 cm−1) and individual spectral widths <20 pm. As expected, a higher front facet reflectivity leads to a significant reduction of feedback related mode hops. Longitudinal modes corresponding to the master oscillator resonator length remain within spectral windows <0.15 nm (3 cm−1), suitable for applications such as Raman spectroscopy and especially shifted excitation Raman difference spectroscopy. Integrating a compact 30 dB optical isolator completely eliminates the observed optical feedback effects. Lateral beam propagation ratios of 1.2 (1/e2) enable easy beam shaping and fiber coupling. Outside of the experimental comparison, the developed MOPAs provide up to 2.7 W of optical output power available for applications.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44242612","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 : 2022-12-12DOI: 10.1088/2399-6528/acd09d
Vincent Lahoche, D. Ousmane Samary, M. Tamaazousti
In this paper, we investigate the large-time behavior for a slightly modified version of the standard p = 2 soft spins dynamics model, including a quartic or higher potential. The equilibrium states of such a model correspond to an effective field theory, which has been recently considered as a novel paradigm for signal detection in data science based on the renormalization group argument. We consider a Langevin-like equation, including a disorder term that leaves in the Wigner or Wishart ensemble. Then we construct a nonperturbative renormalization group formalism valid in the large N limit, where eigenvalues distributions for the disorder can be replaced by their analytic limits, namely the Wigner and Marchenko-Pastur laws. One of the main advantages of this approach is that the interactions remain local in time, avoiding the non-locality arising from the approaches that integrate out the disorder at the partition function level.
{"title":"Functional renormalization group for multilinear disordered Langevin dynamics II:Revisiting the p = 2 spin dynamics for Wigner and Wishart ensembles","authors":"Vincent Lahoche, D. Ousmane Samary, M. Tamaazousti","doi":"10.1088/2399-6528/acd09d","DOIUrl":"https://doi.org/10.1088/2399-6528/acd09d","url":null,"abstract":"In this paper, we investigate the large-time behavior for a slightly modified version of the standard p = 2 soft spins dynamics model, including a quartic or higher potential. The equilibrium states of such a model correspond to an effective field theory, which has been recently considered as a novel paradigm for signal detection in data science based on the renormalization group argument. We consider a Langevin-like equation, including a disorder term that leaves in the Wigner or Wishart ensemble. Then we construct a nonperturbative renormalization group formalism valid in the large N limit, where eigenvalues distributions for the disorder can be replaced by their analytic limits, namely the Wigner and Marchenko-Pastur laws. One of the main advantages of this approach is that the interactions remain local in time, avoiding the non-locality arising from the approaches that integrate out the disorder at the partition function level.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":"7 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42476507","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 : 2022-12-09DOI: 10.1088/2399-6528/acaa89
A. Abawari, Yitagesu Elfaged
This study examines the perturbation effect of temperature and density of moist air on atmospheric variables at 9°1’48″N, 38°44’24″E and 6.324 km above the Earth’s surface. The atmosphere is a compressible neutral moist air flowing on a rotating Earth as a model and it’s basic atmospheric parameters such as gas constant, transport coefficients, mixing ratio and specific heat capacities are considered to be temperature dependent and the Earth’s gravity changes with latitude and altitude. To describe the dynamics, we carried out a numerical computation using finite difference method on an unstaggered grid. Our results revealed that the response of all the variables have a plane wave pattern, in which specific heat capacities (SHCs), resultant wind speed (RWS) and water vapor mixing ratio (MR) increase with time at each latitude but vertical wind speed (VWS), specific enthalpy (SE) and pressure decrease with time at each latitude. The increase of MR with time is the result of water vapor flux into the air parcel and the decrease of SE and increase of RWS with time is the result of thermal energy to mechanical energy transformation. The decrease of VWS with time is the effect of the viscous force due to temperature dependence of viscosity.
{"title":"Computational study of temperature and density perturbations on atmospheric dynamics","authors":"A. Abawari, Yitagesu Elfaged","doi":"10.1088/2399-6528/acaa89","DOIUrl":"https://doi.org/10.1088/2399-6528/acaa89","url":null,"abstract":"This study examines the perturbation effect of temperature and density of moist air on atmospheric variables at 9°1’48″N, 38°44’24″E and 6.324 km above the Earth’s surface. The atmosphere is a compressible neutral moist air flowing on a rotating Earth as a model and it’s basic atmospheric parameters such as gas constant, transport coefficients, mixing ratio and specific heat capacities are considered to be temperature dependent and the Earth’s gravity changes with latitude and altitude. To describe the dynamics, we carried out a numerical computation using finite difference method on an unstaggered grid. Our results revealed that the response of all the variables have a plane wave pattern, in which specific heat capacities (SHCs), resultant wind speed (RWS) and water vapor mixing ratio (MR) increase with time at each latitude but vertical wind speed (VWS), specific enthalpy (SE) and pressure decrease with time at each latitude. The increase of MR with time is the result of water vapor flux into the air parcel and the decrease of SE and increase of RWS with time is the result of thermal energy to mechanical energy transformation. The decrease of VWS with time is the effect of the viscous force due to temperature dependence of viscosity.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45295266","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 : 2022-12-01DOI: 10.1088/2399-6528/aca45e
J. Grant-Jacob, B. Mills
Airborne particulate matter pollution is a global health problem that affects people from all demographics. To reduce the impact of such pollution and enable mitigation and policy planning, quantifying individuals’ exposure to pollution is necessary. To achieve this, effective monitoring of airborne particulates is required, through monitoring of pollution hotspots and sources. Furthermore, since pollution is a global problem, which varies from urban areas to city centres, industrial facilities to inside homes, a variety of sensors might be needed. Current sensing techniques either lack species resolution on a world scale, lack real-time capabilities, or are too expensive or too large for mass deployment. However, recent work using deep learning techniques has expanded the capability of current sensors and allowed the development of new techniques that have the potential for worldwide, species specific, real-time monitoring. Here, it is proposed how deep learning can enable sensor design for the development of small, low-cost sensors for real-time monitoring of particulate matter pollution, whilst unlocking the capability for predicting future particulate events and health inference from particulates, for both individuals and the environment in general.
{"title":"Deep learning in airborne particulate matter sensing: a review","authors":"J. Grant-Jacob, B. Mills","doi":"10.1088/2399-6528/aca45e","DOIUrl":"https://doi.org/10.1088/2399-6528/aca45e","url":null,"abstract":"Airborne particulate matter pollution is a global health problem that affects people from all demographics. To reduce the impact of such pollution and enable mitigation and policy planning, quantifying individuals’ exposure to pollution is necessary. To achieve this, effective monitoring of airborne particulates is required, through monitoring of pollution hotspots and sources. Furthermore, since pollution is a global problem, which varies from urban areas to city centres, industrial facilities to inside homes, a variety of sensors might be needed. Current sensing techniques either lack species resolution on a world scale, lack real-time capabilities, or are too expensive or too large for mass deployment. However, recent work using deep learning techniques has expanded the capability of current sensors and allowed the development of new techniques that have the potential for worldwide, species specific, real-time monitoring. Here, it is proposed how deep learning can enable sensor design for the development of small, low-cost sensors for real-time monitoring of particulate matter pollution, whilst unlocking the capability for predicting future particulate events and health inference from particulates, for both individuals and the environment in general.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49229129","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 : 2022-12-01DOI: 10.1088/2399-6528/acbf04
Steven Blaber, David A. Sivak
We review recent progress in optimal control in stochastic thermodynamics. Theoretical advances provide in-depth insight into minimum-dissipation control with either full or limited (parametric) control, and spanning the limits from slow to fast driving and from weak to strong driving. Known exact solutions give a window into the properties of minimum-dissipation control, which are reproduced by approximate methods in the relevant limits. Connections between optimal-transport theory and minimum-dissipation protocols under full control give deep insight into the properties of optimal control and place bounds on the dissipation of thermodynamic processes. Since minimum-dissipation protocols are relatively well understood and advanced approximation methods and numerical techniques for estimating minimum-dissipation protocols have been developed, now is an opportune time for application to chemical and biological systems.
{"title":"Optimal control in stochastic thermodynamics","authors":"Steven Blaber, David A. Sivak","doi":"10.1088/2399-6528/acbf04","DOIUrl":"https://doi.org/10.1088/2399-6528/acbf04","url":null,"abstract":"We review recent progress in optimal control in stochastic thermodynamics. Theoretical advances provide in-depth insight into minimum-dissipation control with either full or limited (parametric) control, and spanning the limits from slow to fast driving and from weak to strong driving. Known exact solutions give a window into the properties of minimum-dissipation control, which are reproduced by approximate methods in the relevant limits. Connections between optimal-transport theory and minimum-dissipation protocols under full control give deep insight into the properties of optimal control and place bounds on the dissipation of thermodynamic processes. Since minimum-dissipation protocols are relatively well understood and advanced approximation methods and numerical techniques for estimating minimum-dissipation protocols have been developed, now is an opportune time for application to chemical and biological systems.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44067286","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 : 2022-12-01DOI: 10.1088/2399-6528/aca87b
Marco Fuhrmann, A. Musyanovych, R. Thoelen, Hildegard Moebius
Electrostatic Force Microscopy has been proven to be a precise and versatile tool to perform quantitative measurements of the dielectric constant of thin film domains in the nanometer range. However, it is difficult to measure non-planar nanostructures because topographic crosstalk significantly contributes to the measured signal. This topographic crosstalk due to distance changes between tip and substrate measuring non-planar surface structures is still an ongoing issue in literature and falsifies measurements of the dielectric constant of nanostructures and nanoparticles. Tip and substrate form a capacitor based on the contact potential difference between the tip and substrate material. An increase of the distance between tip and substrate causes a repulsive force while a decrease causes an attractive force. Thus, measuring in the so-called lift mode scanning the surface in a second scan following the topography determined by a first scan leads to a mirroring of the non-planar surface structure in the electrostatic signal superimposing the signal from dielectric contrast. In this work we demonstrate that the topographic crosstalk can be avoided by using the linear mode instead of the lift mode. The use of the linear mode now allows the determination of the dielectric constant of single nanoparticles.
{"title":"Determination of the dielectric constant of non-planar nanostructures and single nanoparticles by electrostatic force microscopy","authors":"Marco Fuhrmann, A. Musyanovych, R. Thoelen, Hildegard Moebius","doi":"10.1088/2399-6528/aca87b","DOIUrl":"https://doi.org/10.1088/2399-6528/aca87b","url":null,"abstract":"Electrostatic Force Microscopy has been proven to be a precise and versatile tool to perform quantitative measurements of the dielectric constant of thin film domains in the nanometer range. However, it is difficult to measure non-planar nanostructures because topographic crosstalk significantly contributes to the measured signal. This topographic crosstalk due to distance changes between tip and substrate measuring non-planar surface structures is still an ongoing issue in literature and falsifies measurements of the dielectric constant of nanostructures and nanoparticles. Tip and substrate form a capacitor based on the contact potential difference between the tip and substrate material. An increase of the distance between tip and substrate causes a repulsive force while a decrease causes an attractive force. Thus, measuring in the so-called lift mode scanning the surface in a second scan following the topography determined by a first scan leads to a mirroring of the non-planar surface structure in the electrostatic signal superimposing the signal from dielectric contrast. In this work we demonstrate that the topographic crosstalk can be avoided by using the linear mode instead of the lift mode. The use of the linear mode now allows the determination of the dielectric constant of single nanoparticles.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48068766","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 : 2022-11-30DOI: 10.1088/2399-6528/aca7af
E. Meoto
Two-neutron drip lines of a few single lambda hypernuclei are studied through a phenomenological binding energy model. This model, which is built from the Bethe-Weizsäcker formula, explicitly takes into account hyperon mass and strangeness. For the hypernuclear isotopic chains of the elements C—Mn, the heaviest isotope in each chain that is stable with respect to two-neutron decay is located.
{"title":"Two-neutron drip lines of a few single lambda hypernuclei","authors":"E. Meoto","doi":"10.1088/2399-6528/aca7af","DOIUrl":"https://doi.org/10.1088/2399-6528/aca7af","url":null,"abstract":"Two-neutron drip lines of a few single lambda hypernuclei are studied through a phenomenological binding energy model. This model, which is built from the Bethe-Weizsäcker formula, explicitly takes into account hyperon mass and strangeness. For the hypernuclear isotopic chains of the elements C—Mn, the heaviest isotope in each chain that is stable with respect to two-neutron decay is located.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42298038","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 : 2022-11-17DOI: 10.1088/2399-6528/aca3fb
M. A. Malek, M. Huda, M. K. Islam, S. Lee
In this study, the Lee code is used to compute the characteristics soft x-ray yield (Ysxr) production for nitrogen (N2), oxygen (O2), neon (Ne), and argon (Ar) and bremsstrahlung radiation for hydrogen (H2), deuterium (D2), and helium (He) with pressure variation in PF1000 of 2.5–2.6 MA for D2. In the calculation of characteristic soft x-ray, the corresponding temperature windows of the said gases are set into the code at which they are ionized to their H-like and He-like levels. The focus pinch parameters such as radius ratio (minimum radius of plasma pinch column/anode radius), ion density, specific heat ratio, pinch energy density, self-absorption correction factor, and maximum induced voltage are computed at the optimum pressure of each gas. The obtained pinch plasma temperature range (1.2–2.2) × 106 K of H2, D2, and He is sufficiently high for fully ionized plasmas and the resulting bremsstrahlung radiation (14 J) for He is significantly larger than for H2 (0.26 J) and D2 (0.62 J). The optimum Ysxr of Ne(∼9314 J) at 0.51 Torr with pinch energy density (PED) (∼26 × 108 Jm−3) is found to be the highest whilst for Ar(∼7 J) at 0.019 Torr with (∼1.2 × 108 Jm−3) is the lowest. It is found that the radius ratio (∼0.05) of Ne is 3-fold smaller than that (∼0.16) in Ar. This enhancement of compression in pinch of Ne increases the ion density significantly by a factor of 253 than in Ar gas. Thus, the results show a strong correlation of plasma pinch properties with Ysxr for various gases.
{"title":"Effect of atomic number and pressure on plasma pinch properties and characteristic soft x-ray emission in PF1000","authors":"M. A. Malek, M. Huda, M. K. Islam, S. Lee","doi":"10.1088/2399-6528/aca3fb","DOIUrl":"https://doi.org/10.1088/2399-6528/aca3fb","url":null,"abstract":"In this study, the Lee code is used to compute the characteristics soft x-ray yield (Ysxr) production for nitrogen (N2), oxygen (O2), neon (Ne), and argon (Ar) and bremsstrahlung radiation for hydrogen (H2), deuterium (D2), and helium (He) with pressure variation in PF1000 of 2.5–2.6 MA for D2. In the calculation of characteristic soft x-ray, the corresponding temperature windows of the said gases are set into the code at which they are ionized to their H-like and He-like levels. The focus pinch parameters such as radius ratio (minimum radius of plasma pinch column/anode radius), ion density, specific heat ratio, pinch energy density, self-absorption correction factor, and maximum induced voltage are computed at the optimum pressure of each gas. The obtained pinch plasma temperature range (1.2–2.2) × 106 K of H2, D2, and He is sufficiently high for fully ionized plasmas and the resulting bremsstrahlung radiation (14 J) for He is significantly larger than for H2 (0.26 J) and D2 (0.62 J). The optimum Ysxr of Ne(∼9314 J) at 0.51 Torr with pinch energy density (PED) (∼26 × 108 Jm−3) is found to be the highest whilst for Ar(∼7 J) at 0.019 Torr with (∼1.2 × 108 Jm−3) is the lowest. It is found that the radius ratio (∼0.05) of Ne is 3-fold smaller than that (∼0.16) in Ar. This enhancement of compression in pinch of Ne increases the ion density significantly by a factor of 253 than in Ar gas. Thus, the results show a strong correlation of plasma pinch properties with Ysxr for various gases.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47617572","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 : 2022-11-14DOI: 10.1088/2399-6528/acdd4f
Alessandro Santini, Andrea Solfanelli, S. Gherardini, G. Giachetti
On a quantum superconducting processor we observe partial and infinite-temperature thermalization induced by a sequence of repeated quantum projective measurements, interspersed by a unitary (Hamiltonian) evolution. Specifically, on a qubit and two-qubit systems, we test the state convergence of a monitored quantum system in the limit of a large number of quantum measurements, depending on the non-commutativity of the Hamiltonian and the measurement observable. When the Hamiltonian and observable do not commute, the convergence is uniform towards the infinite-temperature state. Conversely, whenever the two operators have one or more eigenvectors in common in their spectral decomposition, the state of the monitored system converges differently in the subspaces spanned by the measurement observable eigenstates. As a result, we show that the convergence does not tend to a completely mixed (infinite-temperature) state, but to a block-diagonal state in the observable basis, with a finite effective temperature in each measurement subspace. Finally, we quantify the effects of the quantum hardware noise on the data by modelling them by means of depolarizing quantum channels.
{"title":"Observation of partial and infinite-temperature thermalization induced by repeated measurements on a quantum hardware","authors":"Alessandro Santini, Andrea Solfanelli, S. Gherardini, G. Giachetti","doi":"10.1088/2399-6528/acdd4f","DOIUrl":"https://doi.org/10.1088/2399-6528/acdd4f","url":null,"abstract":"On a quantum superconducting processor we observe partial and infinite-temperature thermalization induced by a sequence of repeated quantum projective measurements, interspersed by a unitary (Hamiltonian) evolution. Specifically, on a qubit and two-qubit systems, we test the state convergence of a monitored quantum system in the limit of a large number of quantum measurements, depending on the non-commutativity of the Hamiltonian and the measurement observable. When the Hamiltonian and observable do not commute, the convergence is uniform towards the infinite-temperature state. Conversely, whenever the two operators have one or more eigenvectors in common in their spectral decomposition, the state of the monitored system converges differently in the subspaces spanned by the measurement observable eigenstates. As a result, we show that the convergence does not tend to a completely mixed (infinite-temperature) state, but to a block-diagonal state in the observable basis, with a finite effective temperature in each measurement subspace. Finally, we quantify the effects of the quantum hardware noise on the data by modelling them by means of depolarizing quantum channels.","PeriodicalId":47089,"journal":{"name":"Journal of Physics Communications","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43434660","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}
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