Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S28
M. Raymer, P. Polakos
The quantum nature of light enables potentially revolutionary communication technologies. Key to advancing this area of research is a clear understanding of the concepts of states, modes, fields, and photons. The concept of field modes carries over from classical optics, while the concept of state has to be considered carefully when treating light quantum mechanically. The term 'photon' is an overloaded identifier in the sense that it is often used to refer to either a quantum particle or the state of a field. This overloading, often used without placing in context, has the potential to obfuscate the physical processes that describe the reality we measure. We review the uses and relationships between these concepts using modern quantum optics theory, including the concept of a photon wave function, the modern history of which was moved forward in a groundbreaking paper in this journal by Iwo Bia{l}ynicki-Birula, to whom this article is dedicated.
{"title":"States, Modes, Fields, and Photons in Quantum Optics","authors":"M. Raymer, P. Polakos","doi":"10.12693/APhysPolA.143.S28","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S28","url":null,"abstract":"The quantum nature of light enables potentially revolutionary communication technologies. Key to advancing this area of research is a clear understanding of the concepts of states, modes, fields, and photons. The concept of field modes carries over from classical optics, while the concept of state has to be considered carefully when treating light quantum mechanically. The term 'photon' is an overloaded identifier in the sense that it is often used to refer to either a quantum particle or the state of a field. This overloading, often used without placing in context, has the potential to obfuscate the physical processes that describe the reality we measure. We review the uses and relationships between these concepts using modern quantum optics theory, including the concept of a photon wave function, the modern history of which was moved forward in a groundbreaking paper in this journal by Iwo Bia{l}ynicki-Birula, to whom this article is dedicated.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"211 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76899587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S131
Filip Gampel, M. Gajda
We study evolution of a quantum particle in a harmonic potential whose position and momentum are repeatedly monitored. A back-action of measuring devices is accounted for. Our model utilizes a generalized measurement corresponding to the Positive Operator-Valued Measure. We assume that upon measurement the particle's wavefunction is projected onto one of possible detector states depending on the observed result. We chose these post-measurement states to be moving Gaussian wavepackets. The Wave Function Quantum Monte-Carlo formalism is used to simulate single quantum trajectories of the particle. We show how classical trajectories emerge in course of observation and study in detail dispersion of position and momentum of the particle.
{"title":"On Repeated Measurements of a Quantum Particle in a Harmonic Potential","authors":"Filip Gampel, M. Gajda","doi":"10.12693/APhysPolA.143.S131","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S131","url":null,"abstract":"We study evolution of a quantum particle in a harmonic potential whose position and momentum are repeatedly monitored. A back-action of measuring devices is accounted for. Our model utilizes a generalized measurement corresponding to the Positive Operator-Valued Measure. We assume that upon measurement the particle's wavefunction is projected onto one of possible detector states depending on the observed result. We chose these post-measurement states to be moving Gaussian wavepackets. The Wave Function Quantum Monte-Carlo formalism is used to simulate single quantum trajectories of the particle. We show how classical trajectories emerge in course of observation and study in detail dispersion of position and momentum of the particle.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"497 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78337926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S42
P. Stammer, M. Lewenstein
We start this short note by remembering the beginnings of the Warsaw School of Quantum Optics, evidently stimulated by Iwo Bialynicki-Birula at the Warsaw University, and then Centre for Theoretical Physics of Polish Academy of Sciences, and Adam Kujawski and Zofia Bialynicka-Birula at the Institute of Physics of Polish Academy of Sciences. In the theoretical approaches of the Warsaw School Quantum Field Theory was always present, and Quantum Optics was considered to be Applied Quantum Electrodynamics (QED). All of us who grew up in this fantastic community have carried and are still carrying the gospel to others. In particular, now QED began her run on the red carpet of Super Instense Laser Matter Interactions, Attosecond-physics, and Ultrafast Laser Physics, in general. We will elaborate on the recent progress in this direction, and on the open questions towards future investigations. This paper celebrates the 90th birthday of Prof. Iwo Bialynicki-Birula, our QED guru!
{"title":"Quantum Optics as Applied Quantum Electrodynamics is Back in Town","authors":"P. Stammer, M. Lewenstein","doi":"10.12693/APhysPolA.143.S42","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S42","url":null,"abstract":"We start this short note by remembering the beginnings of the Warsaw School of Quantum Optics, evidently stimulated by Iwo Bialynicki-Birula at the Warsaw University, and then Centre for Theoretical Physics of Polish Academy of Sciences, and Adam Kujawski and Zofia Bialynicka-Birula at the Institute of Physics of Polish Academy of Sciences. In the theoretical approaches of the Warsaw School Quantum Field Theory was always present, and Quantum Optics was considered to be Applied Quantum Electrodynamics (QED). All of us who grew up in this fantastic community have carried and are still carrying the gospel to others. In particular, now QED began her run on the red carpet of Super Instense Laser Matter Interactions, Attosecond-physics, and Ultrafast Laser Physics, in general. We will elaborate on the recent progress in this direction, and on the open questions towards future investigations. This paper celebrates the 90th birthday of Prof. Iwo Bialynicki-Birula, our QED guru!","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"12 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76279315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S52
Alexander Friedrich, D. Moll, M. Freyberger, L. Plimak, W. Schleich
We show that despite the fundamentally different situations, the wave functional of the vacuum in a resonator is identical to that of free space. The infinite product of Gaussian ground state wave functions defining the wave functional of the vacuum translates into an exponential of a sum rather than an integral over the squares of mode amplitudes weighted by the mode volume and a power of the mode wave number. We express this sum by an integral of a bilinear form of the field containing a kernel given by a function of the square root of the negative Laplacian acting on a transverse delta function. For transverse fields it suffices to employ the familiar delta function which allows us to obtain explicit expressions for the kernels of the vector potential, the electric field and the magnetic induction. We show for the example of the vector potential that different mode expansions lead to different kernels. Lastly, we show that the kernels have a close relationship with the Wightman correlation functions of the fields.
{"title":"The Wave Functional of the Vacuum in a Resonator","authors":"Alexander Friedrich, D. Moll, M. Freyberger, L. Plimak, W. Schleich","doi":"10.12693/APhysPolA.143.S52","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S52","url":null,"abstract":"We show that despite the fundamentally different situations, the wave functional of the vacuum in a resonator is identical to that of free space. The infinite product of Gaussian ground state wave functions defining the wave functional of the vacuum translates into an exponential of a sum rather than an integral over the squares of mode amplitudes weighted by the mode volume and a power of the mode wave number. We express this sum by an integral of a bilinear form of the field containing a kernel given by a function of the square root of the negative Laplacian acting on a transverse delta function. For transverse fields it suffices to employ the familiar delta function which allows us to obtain explicit expressions for the kernels of the vector potential, the electric field and the magnetic induction. We show for the example of the vector potential that different mode expansions lead to different kernels. Lastly, we show that the kernels have a close relationship with the Wightman correlation functions of the fields.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"24 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84239729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S78
P. Milonni
The Helmholtz free energy of oscillators in thermal equilibrium with electromagnetic radiation is obtained from the Pauli-Hellmann-Feynman theorem and applied to some aspects of Lamb shifts and van der Waals interactions.
{"title":"Free Energy of Coupled Oscillators: Lamb Shifts and van der Waals Interactions","authors":"P. Milonni","doi":"10.12693/APhysPolA.143.S78","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S78","url":null,"abstract":"The Helmholtz free energy of oscillators in thermal equilibrium with electromagnetic radiation is obtained from the Pauli-Hellmann-Feynman theorem and applied to some aspects of Lamb shifts and van der Waals interactions.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"10 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79191738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S171
M. Kruk, T. Vibel, J. Arlt, P. Kulik, K. Pawłowski, K. Rzka.zewski
We study the statistical properties of a gas of interacting bosons trapped in a box potential in two and three dimensions. Our primary focus is the characteristic temperature $tchar$, i.e. the temperature at which the fluctuations of the number of condensed atoms (or, in 2D, the number of motionless atoms) is maximal. Using the Fock State Sampling method, we show that $tchar$ increases due to interaction. In 3D, this temperature converges to the critical temperature in the thermodynamic limit. In 2D we show the general applicability of the method by obtaining a generalized dependence of the characteristic temperature on the interaction strength. Finally, we discuss the experimental conditions necessary for the verification of our theoretical predictions.
{"title":"Fock State Sampling Method - Characteristic Temperature of Maximal Fluctuations for Interacting Bosons in Box Potentials","authors":"M. Kruk, T. Vibel, J. Arlt, P. Kulik, K. Pawłowski, K. Rzka.zewski","doi":"10.12693/APhysPolA.143.S171","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S171","url":null,"abstract":"We study the statistical properties of a gas of interacting bosons trapped in a box potential in two and three dimensions. Our primary focus is the characteristic temperature $tchar$, i.e. the temperature at which the fluctuations of the number of condensed atoms (or, in 2D, the number of motionless atoms) is maximal. Using the Fock State Sampling method, we show that $tchar$ increases due to interaction. In 3D, this temperature converges to the critical temperature in the thermodynamic limit. In 2D we show the general applicability of the method by obtaining a generalized dependence of the characteristic temperature on the interaction strength. Finally, we discuss the experimental conditions necessary for the verification of our theoretical predictions.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88104603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S13
S. Evans, J. Rafelski
We implement a longstanding proposal by Weisskopf to apply virtual polarization corrections to the in/out external fields in study of the Euler-Heisenberg-Schwinger effective action. Our approach requires distinguishing the electromagnetic and polarization fields based on mathematical tools developed by Bia{l}ynicki-Birula, originally for the Born-Infeld action. Our solution is expressed as a differential equation where the one-loop effective action serves as input. As a first result of our approach, we recover the higher-order one-cut reducible loop diagrams discovered by Gies and Karbstein.
{"title":"Improving Euler-Heisenberg-Schwinger Effective Action with Dressed Photons","authors":"S. Evans, J. Rafelski","doi":"10.12693/APhysPolA.143.S13","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S13","url":null,"abstract":"We implement a longstanding proposal by Weisskopf to apply virtual polarization corrections to the in/out external fields in study of the Euler-Heisenberg-Schwinger effective action. Our approach requires distinguishing the electromagnetic and polarization fields based on mathematical tools developed by Bia{l}ynicki-Birula, originally for the Born-Infeld action. Our solution is expressed as a differential equation where the one-loop effective action serves as input. As a first result of our approach, we recover the higher-order one-cut reducible loop diagrams discovered by Gies and Karbstein.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"2015 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87845008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.12693/APhysPolA.143.S140
J. Mostowski, J. Pietraszewicz
We discuss the possibility of localizing an electron in a highly excited Rydberg state. The second-order correlation of emitted photons is the tool for the determination of electron position. This second-order correlation of emitted radiation and, therefore, the correlation of operators describing the acceleration of the electron allows for a partial localization of the electron in its orbit. The correlation function is found by approximating the transition matrix elements by their values in the classical limit. It is shown that the second-order correlation, depending on two times, is a function of the time difference and is a periodic function of this argument with the period equal to the period of the corresponding classical motion. The function has sharp maxima corresponding to large electron acceleration in the vicinity of the ``perihelion.'' This allows the localization of the electron in its consecutive approach to the perihelion point.
{"title":"Electron Localization in Rydberg States","authors":"J. Mostowski, J. Pietraszewicz","doi":"10.12693/APhysPolA.143.S140","DOIUrl":"https://doi.org/10.12693/APhysPolA.143.S140","url":null,"abstract":"We discuss the possibility of localizing an electron in a highly excited Rydberg state. The second-order correlation of emitted photons is the tool for the determination of electron position. This second-order correlation of emitted radiation and, therefore, the correlation of operators describing the acceleration of the electron allows for a partial localization of the electron in its orbit. The correlation function is found by approximating the transition matrix elements by their values in the classical limit. It is shown that the second-order correlation, depending on two times, is a function of the time difference and is a periodic function of this argument with the period equal to the period of the corresponding classical motion. The function has sharp maxima corresponding to large electron acceleration in the vicinity of the ``perihelion.'' This allows the localization of the electron in its consecutive approach to the perihelion point.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"128 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85336365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.12693/aphyspola.143.400
H. Brahimi, A. Keffous, N. Haine, B. Rahal, Y. Larbah
The last decades have seen a lot of work and development on new methods of neutron detection that would replace 3 He gas-based detectors, a device widely used due to its efficiency, which is being phased out due to the scarcity of 3 He gas and its high cost. The work showed that a combination of inorganic materials (Si, 6 LiF) could represent a viable basis for the development of new generations of thermal neutron detectors. This type of device is based on a silicon detector coupled to 6 LiF thin film converters. In this work, a model has been developed based on the fabricated silicon detector with a Schottky surface barrier associated with different thicknesses of 6 LiF films. To study its behavior as a function of the different film thicknesses, the model was characterized using a thermal neutron flux from the source (AmBe-OB26). Preliminary results show that it is possible to measure low-energy neutrons with an average detection efficiency of about 1%, a sensibility of 10 ± 0 . 1 cps on the 3 H peak, and insensibility to gamma radiation < 10 − 6 , with a thin films size of about 2 µ m. In this paper, we will present a state of the art of detector design, an evaluation of its characteristics (efficiency, resolution, dead time, proper motion), and a clarification of the influence of other parameters on the shape of the spectrum, highlighting the possibility of improving its detection efficiency to make it high, with a gamma/neutron rejection capability comparable to the 3 He gas detector.
{"title":"Study and Characterization of LiF Thin Film Combined with a Silicon Detector for Neutron Metrology","authors":"H. Brahimi, A. Keffous, N. Haine, B. Rahal, Y. Larbah","doi":"10.12693/aphyspola.143.400","DOIUrl":"https://doi.org/10.12693/aphyspola.143.400","url":null,"abstract":"The last decades have seen a lot of work and development on new methods of neutron detection that would replace 3 He gas-based detectors, a device widely used due to its efficiency, which is being phased out due to the scarcity of 3 He gas and its high cost. The work showed that a combination of inorganic materials (Si, 6 LiF) could represent a viable basis for the development of new generations of thermal neutron detectors. This type of device is based on a silicon detector coupled to 6 LiF thin film converters. In this work, a model has been developed based on the fabricated silicon detector with a Schottky surface barrier associated with different thicknesses of 6 LiF films. To study its behavior as a function of the different film thicknesses, the model was characterized using a thermal neutron flux from the source (AmBe-OB26). Preliminary results show that it is possible to measure low-energy neutrons with an average detection efficiency of about 1%, a sensibility of 10 ± 0 . 1 cps on the 3 H peak, and insensibility to gamma radiation < 10 − 6 , with a thin films size of about 2 µ m. In this paper, we will present a state of the art of detector design, an evaluation of its characteristics (efficiency, resolution, dead time, proper motion), and a clarification of the influence of other parameters on the shape of the spectrum, highlighting the possibility of improving its detection efficiency to make it high, with a gamma/neutron rejection capability comparable to the 3 He gas detector.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"45 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75111329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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