: We observed the flat-spectrum radio quasar 4C 29.45 in the BVRI optical bands for 39 nights from February 2022 to July 2022 with the T60 telescope at T¨UB˙ITAK National Observatory (TUG) in Turkey. In this study, we aimed to study flux, color, and spectral variability on short timescales. The object was in an active (bright) phase with an average optical R-band brightness of 14.7 mag and was variable in the BVRI bands throughout the monitoring period. We analyzed the flux variability during our observation period, and the variability amplitudes in V, R, and I bands were determined to be 220%, 208%, and 209%, respectively. Optical spectral energy distributions of 4C 29.45 were derived from the observational data of 33 nights, indicating spectral indices ranging from 1.032 to 1.573. We found modest correlations between optical light curves, and between R-band light curve and spectral indices, suggesting that the time lag ranges from several hours to days. Investigation on relation between spectral and color indices versus R-band magnitude revealed achromatic trend during the bright phase of 4C 29.45 in the first half of 2022. Our periodicity search suggested that the periodicity would be larger than 100 days, and no significant signal for periodicity was found for short timescales.
{"title":"Shortterm optical variability of 4C 29.45","authors":"A. Özdönmez","doi":"10.55730/1300-0101.2742","DOIUrl":"https://doi.org/10.55730/1300-0101.2742","url":null,"abstract":": We observed the flat-spectrum radio quasar 4C 29.45 in the BVRI optical bands for 39 nights from February 2022 to July 2022 with the T60 telescope at T¨UB˙ITAK National Observatory (TUG) in Turkey. In this study, we aimed to study flux, color, and spectral variability on short timescales. The object was in an active (bright) phase with an average optical R-band brightness of 14.7 mag and was variable in the BVRI bands throughout the monitoring period. We analyzed the flux variability during our observation period, and the variability amplitudes in V, R, and I bands were determined to be 220%, 208%, and 209%, respectively. Optical spectral energy distributions of 4C 29.45 were derived from the observational data of 33 nights, indicating spectral indices ranging from 1.032 to 1.573. We found modest correlations between optical light curves, and between R-band light curve and spectral indices, suggesting that the time lag ranges from several hours to days. Investigation on relation between spectral and color indices versus R-band magnitude revealed achromatic trend during the bright phase of 4C 29.45 in the first half of 2022. Our periodicity search suggested that the periodicity would be larger than 100 days, and no significant signal for periodicity was found for short timescales.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43179295","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}
An important issue in phenomenological macroscopic electrodynamics of moving media is the definition of the energy and momentum of the electromagnetic field in matter. Rather surprisingly, this topic has demonstrated a remarkable longevity, and the problem of the electromagnetic energy and momentum in matter remained open, despite numerous theoretical and experimental investi-gations. We overview the definition of the momentum of light in matter and demonstrate that, for the correct understanding of the problem, one needs to carefully distinguish situations when the material medium is modeled either as a background for light or as a dynamical part of the total system. The status of Minkowski and Abraham energy-momentum tensors of the electromagnetic field is clarified for the two particular types of complex matter, the spinning fluid and the liquid crystal medium, and summarized for the case of general anisotropic moving material media with a linear constitutive law.
{"title":"Momentum of light in complex media","authors":"Y. Obukhov","doi":"10.55730/1300-0101.2719","DOIUrl":"https://doi.org/10.55730/1300-0101.2719","url":null,"abstract":"An important issue in phenomenological macroscopic electrodynamics of moving media is the definition of the energy and momentum of the electromagnetic field in matter. Rather surprisingly, this topic has demonstrated a remarkable longevity, and the problem of the electromagnetic energy and momentum in matter remained open, despite numerous theoretical and experimental investi-gations. We overview the definition of the momentum of light in matter and demonstrate that, for the correct understanding of the problem, one needs to carefully distinguish situations when the material medium is modeled either as a background for light or as a dynamical part of the total system. The status of Minkowski and Abraham energy-momentum tensors of the electromagnetic field is clarified for the two particular types of complex matter, the spinning fluid and the liquid crystal medium, and summarized for the case of general anisotropic moving material media with a linear constitutive law.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44804474","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}
We give a pedagogical introduction to black holes (BHs) greybody factors (GFs) and quasinormal modes (QNMs) and share the recent developments on those subjects. To this end, we present some particular analytical and approximation techniques for the computations of the GFs and QNMs. We first review the gravitational GFs and show how they are analytically calculated for static and spherically symmetric higher dimensional BHs, consisting the charged BHs and existence of cosmological constant (i.e., de Sitter (dS)/anti-de Sitter (AdS)AdS BHs). The computations performed involve both the low-energy (having real and small frequencies) and the asymptotic (having extremely high frequency of the scattered wave throughout the imaginary axis) cases. A generic method is discussed at low frequencies. This method can be used for all three types of spacetime asymptotics and it is unaffected by the BH’s features. For asymptotically dS BHs, GF varies de-pending on whether the spacetime dimension is even or odd, and is proportional to the ratio of the event and cosmic horizon areas. At asymptotic frequencies, the GFs can be computed by using a matching technique inspired by the monodromy method. In the meantime, we also make a general literature review on the matching technique in a separate section. While the GFs for charged or asymptotically dS BHs are generated by non-trivial functions, the GF for asymptotically AdS BHs is precisely one: pure black-body emission. QNMs, which are solutions to the relevant perturbation equations that satisfy the boundary conditions for purely outgoing (gravitational) waves at spatial infinity and purely ingoing (gravitational) waves at the event horizon, are considered using some particular analytical (like the matching technique) and approximation methods. In this study, our primary focus will be on the bosonic and fermionic GFs and QNMs of various BH and brane geometries and reveal the fingerprints of the invisibles with the radiation spectra to be obtained by the WKB approximation and bounding the Bogoliubov coefficients (together with the Miller-Good transformation) methods.
{"title":"Topical Review: greybody factors and quasinormal modes for black holes invarious theories - fingerprints of invisibles","authors":".. Sakalli, Sara Kanzi","doi":"10.55730/1300-0101.2691","DOIUrl":"https://doi.org/10.55730/1300-0101.2691","url":null,"abstract":"We give a pedagogical introduction to black holes (BHs) greybody factors (GFs) and quasinormal modes (QNMs) and share the recent developments on those subjects. To this end, we present some particular analytical and approximation techniques for the computations of the GFs and QNMs. We first review the gravitational GFs and show how they are analytically calculated for static and spherically symmetric higher dimensional BHs, consisting the charged BHs and existence of cosmological constant (i.e., de Sitter (dS)/anti-de Sitter (AdS)AdS BHs). The computations performed involve both the low-energy (having real and small frequencies) and the asymptotic (having extremely high frequency of the scattered wave throughout the imaginary axis) cases. A generic method is discussed at low frequencies. This method can be used for all three types of spacetime asymptotics and it is unaffected by the BH’s features. For asymptotically dS BHs, GF varies de-pending on whether the spacetime dimension is even or odd, and is proportional to the ratio of the event and cosmic horizon areas. At asymptotic frequencies, the GFs can be computed by using a matching technique inspired by the monodromy method. In the meantime, we also make a general literature review on the matching technique in a separate section. While the GFs for charged or asymptotically dS BHs are generated by non-trivial functions, the GF for asymptotically AdS BHs is precisely one: pure black-body emission. QNMs, which are solutions to the relevant perturbation equations that satisfy the boundary conditions for purely outgoing (gravitational) waves at spatial infinity and purely ingoing (gravitational) waves at the event horizon, are considered using some particular analytical (like the matching technique) and approximation methods. In this study, our primary focus will be on the bosonic and fermionic GFs and QNMs of various BH and brane geometries and reveal the fingerprints of the invisibles with the radiation spectra to be obtained by the WKB approximation and bounding the Bogoliubov coefficients (together with the Miller-Good transformation) methods.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49430954","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}
A consistent variational derivation of the Majorana 4-spinor field equations coupled to Einstein’s theory of gravitation is given. The equivalence of the first and the second order variational field equations is explicitly demonstrated. The Lagrange multiplier 2-forms we use turn out to be precisely the Belinfante-Rosenfeld 2-forms that are needed to symmetrize the canonical energy-momentum tensor of the Majorana spinor.
{"title":"Variational field equations of a Majorana neutrino coupled to Einstein's theory of general relativity","authors":"T. Dereli, Yorgo Şenikoğlu","doi":"10.55730/1300-0101.2722","DOIUrl":"https://doi.org/10.55730/1300-0101.2722","url":null,"abstract":"A consistent variational derivation of the Majorana 4-spinor field equations coupled to Einstein’s theory of gravitation is given. The equivalence of the first and the second order variational field equations is explicitly demonstrated. The Lagrange multiplier 2-forms we use turn out to be precisely the Belinfante-Rosenfeld 2-forms that are needed to symmetrize the canonical energy-momentum tensor of the Majorana spinor.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44293310","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}
The field of silicon photonics is based on introducing and exploiting advanced optical functionality. Current efforts in the field are based on conventional micro/nanofabrication methods, leading to optical functionality over wafer surfaces. A complementary and emerging field is introducing analogous optics directly within the wafer using lasers. Here we investigate the theoretical feasibility of a subclass of such optics, photonic crystals. Our efforts will guide future experimental efforts towards in-chip spectral control.
{"title":"Investigating the potential of laser-written one-dimensional photonic crystals inside silicon","authors":"O. Tokel","doi":"10.55730/1300-0101.2720","DOIUrl":"https://doi.org/10.55730/1300-0101.2720","url":null,"abstract":"The field of silicon photonics is based on introducing and exploiting advanced optical functionality. Current efforts in the field are based on conventional micro/nanofabrication methods, leading to optical functionality over wafer surfaces. A complementary and emerging field is introducing analogous optics directly within the wafer using lasers. Here we investigate the theoretical feasibility of a subclass of such optics, photonic crystals. Our efforts will guide future experimental efforts towards in-chip spectral control.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46053112","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}
: The study of the properties of doubly heavy baryons represents a promising area in particle physics. It can provide us with information about Cabibbo–Kobayashi–Maskawa (CKM) matrix elements and the low energy dynamics of QCD. They have a very rich phenomenology. The investigation of weak, electromagnetic, and strong decays has a vital importance for understanding the dynamics of doubly heavy baryons. The main ingredients of such studies are the spectroscopic parameters, the strong coupling constants, and the transition form factors. For calculations of these quantities, non-perturbative methods are needed. One of these methods is the QCD sum rules. In the present work, we review our studies on the properties of the doubly heavy baryons within the sum rules method, focusing mainly on the mass and strong coupling constants of the doubly heavy baryons. In addition, the radiative decays of doubly heavy baryons are estimated using the vector dominance model. We also make few remarks on the semileptonic decays of the doubly heavy baryons.
{"title":"Properties of doubly heavy baryons in QCD","authors":"Takhmasib Aliyev, Selçuk Bi̇lmi̇ş","doi":"10.55730/1300-0101.2688","DOIUrl":"https://doi.org/10.55730/1300-0101.2688","url":null,"abstract":": The study of the properties of doubly heavy baryons represents a promising area in particle physics. It can provide us with information about Cabibbo–Kobayashi–Maskawa (CKM) matrix elements and the low energy dynamics of QCD. They have a very rich phenomenology. The investigation of weak, electromagnetic, and strong decays has a vital importance for understanding the dynamics of doubly heavy baryons. The main ingredients of such studies are the spectroscopic parameters, the strong coupling constants, and the transition form factors. For calculations of these quantities, non-perturbative methods are needed. One of these methods is the QCD sum rules. In the present work, we review our studies on the properties of the doubly heavy baryons within the sum rules method, focusing mainly on the mass and strong coupling constants of the doubly heavy baryons. In addition, the radiative decays of doubly heavy baryons are estimated using the vector dominance model. We also make few remarks on the semileptonic decays of the doubly heavy baryons.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42247916","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}
{"title":"On an Econophysics Model","authors":"Miron Kaufman","doi":"10.55730/1300-0101.2725","DOIUrl":"https://doi.org/10.55730/1300-0101.2725","url":null,"abstract":"","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43300801","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}
{"title":"Extinction and growth on an inhomogeneous Seascape","authors":"Tung X. Tran, M. Kardar","doi":"10.55730/1300-0101.2724","DOIUrl":"https://doi.org/10.55730/1300-0101.2724","url":null,"abstract":"","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41508958","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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