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Publication Metadata only Metric-bourbaki algebroids: cartan calculus for m-theory(Elsevier, 2024) Çatal-Özer, Aybike; Doğan, Keremcan; Department of Physics; Dereli, Tekin; Department of Physics; College of SciencesString and M theories seem to require generalizations of usual notions of differential geometry on smooth manifolds. Such generalizations usually involve extending the tangent bundle to larger vector bundles equipped with various algebroid structures such as Courant algebroids, higher Courant algebroids, metric algebroids, or G-algebroids. The most general geometric scheme is not well understood yet, and a unifying framework for such algebroid structures is needed. Our aim in this paper is to propose such a general framework. Our strategy is to follow the hierarchy of defining axioms for a Courant algebroid: almostCourant - metric - pre -Courant - Courant. In particular, we focus on the symmetric part of the bracket and the metric invariance property, and try to make sense of them in a manner as general as possible. These ideas lead us to define new algebroid structures which we dub Bourbaki and metric-Bourbaki algebroids, together with their almostand pre -versions. For a special case of metric-Bourbaki algebroids that we call exact, we construct a collection of maps which generalize the Cartan calculus of exterior derivative, Lie derivative and interior product. This is done by a kind of reverse -mathematical analysis of the Severa classification of exact Courant algebroids. By abstracting crucial properties of this collection of maps, we define the notion of Bourbaki calculus. Conversely, given an arbitrary Bourbaki calculus, we construct a metric-Bourbaki algebroid by building up a standard bracket that is analogous to the Dorfman bracket. Moreover, we prove that any exact metric-Bourbaki algebroid satisfying some further conditions has to have a bracket that is the twisted version of the standard bracket; a partly analogous result to Severa classification. We prove that many physically and mathematically motivated algebroids from the literature are examples of these new algebroids, and when possible we construct a Bourbaki calculus on them. In particular, we show that the Cartan calculus can be seen as the Bourbaki calculus corresponding to an exact higher Courant algebroid. We also point out examples of Bourbaki calculi including the generalization of the Cartan calculus on vector bundle valued forms. One straightforward generalization of our constructions might be done by replacing the tangent bundle with an arbitrary Lie algebroid A. This step allows us to define an extension of our results, A -version, and extend our main results for them while proving many other algebroids from the literature fit into this framework.Publication Metadata only Mesocarnivores den site selection in arid ecosystems; a case study of Rüppell's fox and sand cat in central Iran(Elsevier, 2024) Feizabadi, Hossein Akbari; Ashrafi, Sohrab; Hemami, Mahmoud R.; Ahmadi, Mohsen; Department of Physics; Naderi, Mortaza; Department of Physics; College of SciencesUnderstanding the relationships between species and their pattern of coexistence is essential in conservation planning. Ruppell's fox and sand cat are two poorly known species of desert areas that coexist in most parts of the desert belt of Africa and the Middle East. However, their habitat selection in many parts of their distribution are unknown. In this research, using the data collected from a three-year monitoring plan, we investigated the relationship between the den sites of Ruppell's fox and sand cat and habitat variables based on the generalized linear mixed model (GLMM) method. The results showed that for Ruppell's foxes, only the density of rodent burrows had a significant and positive effect. In the sand cat model, in addition to prey, vegetation density (P-value < 0.05) and vegetation height (P -value < 0.10) had significantly positive effects and elevation had a significantly negative effect (P-value < 0.10). We found that the sand cat is more specialized in habitat selection and depends more on the habitat cover. While the Ruppell's fox chose a more diverse range of soil and vegetation classes, the sand cat selected its den sites exclusively in sandy loam soils with the predominant cover of Haloxylon spp. and Caligonum spp. Acting as a generalist species, Ruppell's fox displayed a more pronounced response to human presence and selected dens with a broader view of their surroundings. These findings enhance our understanding of mesocarnivore coexistence in desert regions and provide valuable insights for the conservation planning of these species.Publication Metadata only Objective-free ultrasensitive biosensing on large-area metamaterial surfaces in the near-IR(AMER CHEMICAL SOC, 2024) Department of Physics; Ramazanoğlu, Serap Aksu; Öktem, Evren; Department of Physics; College of Sciences; Graduate School of Sciences and EngineeringPlasmonic metamaterials have opened new avenues in medical diagnostics. However, the transfer of the technology to the markets has been delayed due to multiple challenges. The need of bulky optics for signal reading from nanostructures patterned on submillimeter area limits the miniaturization of the devices. The use of objective-free optics can solve this problem, which necessitates large area patterning of the nanostructures. In this work, we utilize laser interference lithography (LIL) to pattern nanodisc-shaped metamaterial absorber nanoantennas over a large area (4 cm(2)) within minutes. The introduction of a sacrificial layer during the fabrication process enables an inverted hole profile and a well-controlled liftoff, which ensures perfectly defined uniform nanopatterning almost with no defects. Furthermore, we use a macroscopic reflection probe for optical characterization in the near-IR, including the detection of the binding kinematics of immunologically relevant proteins. We show that the photonic quality of the plasmonic nanoantennas commensurates with electron-beam-lithography-fabricated ones over the whole area. The refractive index sensitivity of the LIL-fabricated metasurface is determined as 685 nm per refractive index unit, which demonstrates ultrasensitive detection. Moreover, the fabricated surfaces can be used multiple times for biosensing without losing their optical quality. The combination of rapid and large area nanofabrication with a simple optical reading not only simplifies the detection process but also makes the biosensors more environmentally friendly and cost-effective. Therefore, the improvements provided in this work will empower researchers and industries for accurate and real-time analysis of biological systems.Publication Metadata only Contrast improvement through a Generative Adversarial Network (GAN) by utilizing a dataset obtained from a line-scanning confocal microscope(SPIE, 2024) Department of Physics; Kiraz, Alper; Morova, Berna; Bavili, Nima; Ketabchi, Amir Mohammad; Department of Physics; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); College of Sciences; Graduate School of Sciences and EngineeringConfocal microscopy offers enhanced image contrast and signal-to-noise ratio compared to wide-field illumination microscopy, achieved by effectively eliminating out-of-focus background noise. In our study, we initially showcase the functionality of a line-scanning confocal microscope aligned through the utilization of a Digital Light Projector (DLP) and a rolling shutter CMOS camera. In this technique, a sequence of illumination lines is projected onto a sample using a DLP and focusing objective (50X, NA=0.55). The reflected light is imaged with the camera. Line-scanning confocal imaging is accomplished by synchronizing the illumination lines with the rolling shutter of the sensor, leading to a substantial enhancement of approximately 50% in image contrast. Subsequently, this setup is employed to create a dataset comprising 500 pairs of images of paper tissue. This dataset is employed for training a Generative Adversarial Network (cGAN). Roughly 45% contrast improvement was measured in the test images for the trained network, in comparison to the ground-truth images.Publication Metadata only Temporal evolution of entropy and chaos in low amplitude seismic wave prior to an earthquake(Pergamon-Elsevier Science Ltd, 2023) Akilli, Mahmut; Ak, Mine; Department of Physics; Yılmaz, Nazmi; Department of Physics; College of SciencesThis study investigates the temporal changes of entropy and chaos in low-amplitude continuous seismic wave data prior to two moderate-level earthquakes. Specifically, we examine seismic signals before and during the Istanbul-Turkey earthquake of September 26, 2019 (M = 5.7), and the Duzce-Turkey earthquake of November 17, 2021 (M = 5.2), which occurred near the Marmara Sea region on the north-Anatolian fault line. We aim to identify changes in complexity and chaotic characteristics in the pre-earthquake seismic waves and explore the possibility of earthquake forecasting minutes before an earthquake. To accomplish this, we utilize windowed scalogram entropy and sample entropy methods and compared the results with Lyapunov exponents and windowed scale index. Our findings indicate that measuring the temporal change of entropy using windowed scalogram entropy is sensitive to the change in complexity due to the frequency shifts during the weak ground motion approaching an earthquake.On the other hand, Lyapunov exponents and sample entropy appear more effective in their response to the change in complexity and chaotic characteristics due to the change in the signal amplitude. Additionally, the windowed scale index can detect temporal fluctuations in the aperiodicity of the signal. Overall, our results suggest that all four methods can be valuable in characterizing complexity and chaos in short-time pre -earthquake seismic signals, differentiating earthquakes, and contributing to the development of earthquake forecasting techniques.Publication Metadata only Tackling the focal shift effect for metalenses(IOP Publishing Ltd, 2024) Department of Physics; Ali, Farhan; Yazdaanpanah, Ramin; Ramazanoğlu, Serap Aksu; Department of Physics; Graduate School of Sciences and Engineering; College of SciencesWe present a theoretical analysis aimed at comprehending and mitigating the focal shift phenomenon in planar dielectric metalenses. To conduct this analysis, we introduce metalens designs consisting of silicon and germanium nanoblocks on a calcium fluoride substrate, operating in the mid-IR frequency range. The lensing performance of these metalenses is investigated using the finite-difference time-domain method, and they operate at wavelengths of 3 and 4 mu m with a polarization conversion efficiency close to unity. Our findings indicate a strong correlation between the focal shift phenomena on dielectric metalenses and the numerical aperture (NA), revealing that increasing the Fresnel number is not always an effective approach to minimizing the focal shift. In contrast to previous studies, we define a critical NA, independent of the lens size, where the focal shift reaches a minimum, resulting in a symmetric focal intensity distribution and ultimately yielding a better-performing metalens. We demonstrate that for NAs greater than the determined critical value, a positive focal shift is observed on planar metalenses, diverging from the conventional negative shift predicted by existing models. Additionally, we show that by selecting a metalens within a specific NA range and with smaller diameters, high focusing efficiencies can be achieved. The focusing efficiency of the studied metalenses is measured as high as 70%, marking one of the best values reported for the IR range to date. These results serve as a guide for improving the agreement between experimental and designed metalens features, enhancing their practical applications.Publication Metadata only Terrestrial very-long-baseline atom interferometry: workshop summary(AIP Publishing, 2024) Abend, Sven; Allard, Baptiste; Alonso, Ivan; Antoniadis, John; Araujo, Henrique; Arduini, Gianluigi; Arnold, Aidan S.; Asano, Tobias; Augst, Nadja; Badurina, Leonardo; Balaz, Antun; Banks, Hannah; Barone, Michele; Barsanti, Michele; Bassi, Angelo; Battelier, Baptiste; Baynham, Charles F. A.; Beaufils, Quentin; Belic, Aleksandar; Beniwal, Ankit; Bernabeu, Jose; Bertinelli, Francesco; Bertoldi, Andrea; Biswas, Ikbal Ahamed; Blas, Diego; Boegel, Patrick; Bogojevic, Aleksandar; Boehm, Jonas; Boehringer, Samuel; Bongs, Kai; Bouyer, Philippe; Brand, Christian; Brimis, Apostolos; Buchmueller, Oliver; Cacciapuoti, Luigi; Calatroni, Sergio; Canuel, Benjamin; Caprini, Chiara; Caramete, Ana; Caramete, Laurentiu; Carlesso, Matteo; Carlton, John; Casariego, Mateo; Charmandaris, Vassilis; Chen, Yu-Ao; Chiofalo, Maria Luisa; Cimbri, Alessia; Coleman, Jonathon; Constantin, Florin Lucian; Contaldi, Carlo R.; Cui, Yanou; Ros, Elisa Da; Davies, Gavin; Rosendo, Esther del Pino; Deppner, Christian; Derevianko, Andrei; de Rham, Claudia; De Roeck, Albert; Derr, Daniel; Di Pumpo, Fabio; Djordjevic, Goran S.; Doebrich, Babette; Domokos, Peter; Dornan, Peter; Doser, Michael; Drougakis, Giannis; Dunningham, Jacob; Duspayev, Alisher; Easo, Sajan; Eby, Joshua; Efremov, Maxim; Ekelof, Tord; Elertas, Gedminas; Ellis, John; Evans, David; Fadeev, Pavel; Fani, Mattia; Fassi, Farida; Fattori, Marco; Fayet, Pierre; Felea, Daniel; Feng, Jie; Friedrich, Alexander; Fuchs, Elina; Gaaloul, Naceur; Gao, Dongfeng; Gardner, Susan; Garraway, Barry; Gauguet, Alexandre; Gerlach, Sandra; Gersemann, Matthias; Gibson, Valerie; Giese, Enno; Giudice, Gian F.; Glasbrenner, Eric P.; Guendogan, Mustafa; Haehnelt, Martin; Hakulinen, Timo; Hammerer, Klemens; Hanimeli, Ekim T.; Harte, Tiffany; Hawkins, Leonie; Hees, Aurelien; Heise, Jaret; Henderson, Victoria A.; Herrmann, Sven; Hird, Thomas M.; Hogan, Jason M.; Holst, Bodil; Holynski, Michael; Hussain, Kamran; Janson, Gregor; Jeglic, Peter; Jelezko, Fedor; Kagan, Michael; Kalliokoski, Matti; Kasevich, Mark; Kehagias, Alex; Kilian, Eva; Koley, Soumen; Konrad, Bernd; Kopp, Joachim; Kornakov, Georgy; Kovachy, Tim; Krutzik, Markus; Kumar, Mukesh; Kumar, Pradeep; Laemmerzahl, Claus; Landsberg, Greg; Langlois, Mehdi; Lanigan, Bryony; Lellouch, Samuel; Leone, Bruno; Poncin-Lafitte, Christophe Le; Lewicki, Marek; Leykauf, Bastian; Lezeik, Ali; Lombriser, Lucas; Luis Lopez-Gonzalez, J.; Lopez Asamar, Elias; Monjaraz, Cristian Lopez; Luciano, Giuseppe Gaetano; Mahmoud, M. A.; Maleknejad, Azadeh; Krutzik, Markus; Marteau, Jacques; Massonnet, Didier; Mazumdar, Anupam; McCabe, Christopher; Meister, Matthias; Menu, Jonathan; Messineo, Giuseppe; Micalizio, Salvatore; Millington, Peter; Milosevic, Milan; Mitchell, Jeremiah; Montero, Mario; Morley, Gavin W.; Mueller, Juergen; Ni, Wei-Tou; Noller, Johannes; Odzak, Senad; Oi, Daniel K. L.; Omar, Yasser; Pahl, Julia; Paling, Sean; Pandey, Saurabh; Pappas, George; Pareek, Vinay; Pasatembou, Elizabeth; Pelucchi, Emanuele; dos Santos, Franck Pereira; Piest, Baptist; Pikovski, Igor; Pilaftsis, Apostolos; Plunkett, Robert; Poggiani, Rosa; Prevedelli, Marco; Puputti, Julia; Veettil, Vishnupriya Puthiya; Quenby, John; Rafelski, Johann; Rajendran, Surjeet; Rasel, Ernst M.; Sfar, Haifa Rejeb; Reynaud, Serge; Richaud, Andrea; Rodzinka, Tangui; Roura, Albert; Rudolph, Jan; Sabulsky, Dylan O.; Safronova, Marianna S.; Santamaria, Luigi; Schilling, Manuel; Schkolnik, Vladimir; Schleich, Wolfgang P.; Schlippert, Dennis; Schneider, Ulrich; Schreck, Florian; Schubert, Christian; Schwersenz, Nico; Semakin, Aleksei; Sergijenko, Olga; Shao, Lijing; Shipsey, Ian; Singh, Rajeev; Smerzi, Augusto; Sopuerta, Carlos F.; Spallicci, Alessandro D. A. M.; Stefanescu, Petruta; Stergioulas, Nikolaos; Stroehle, Jannik; Struckmann, Christian; Tentindo, Silvia; Throssell, Henry; Tino, Guglielmo M.; Tinsley, Jonathan N.; Mircea, Ovidiu Tintareanu; Tkalcec, Kimberly; Tolley, Andrew J.; Tornatore, Vincenza; Torres-Orjuela, Alejandro; Treutlein, Philipp; Trombettoni, Andrea; Tsai, Yu-Dai; Ufrecht, Christian; Ulmer, Stefan; Valuch, Daniel; Vaskonen, Ville; Vazquez-Aceves, Veronica; Vitanov, Nikolay V.; Vogt, Christian; von Klitzing, Wolf; Vukics, Andras; Walser, Reinhold; Wang, Jin; Warburton, Niels; Webber-Date, Alexander; Wenzlawski, Andre; Werner, Michael; Williams, Jason; Windpassinger, Patrick; Wolf, Peter; Woerner, Lisa; Xuereb, Andre; Yahia, Mohamed E.; Cruzeiro, Emmanuel Zambrini; Zarei, Moslem; Zhan, Mingsheng; Zhou, Lin; Zupan, Jure; Zupanic, Erik; Department of Physics; Müstecaplıoğlu, Özgür Esat; Department of Physics; College of SciencesThis document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more kilometer--scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.Publication Metadata only Landau levels versus hydrogen atom(MDPI, 2024) Nounahon, Philippe; Popov, Todor; Department of Physics; Dereli, Tekin; Department of Physics; College of SciencesThe Landau problem and harmonic oscillator in the plane share a Hilbert space that carries the structure of Dirac's remarkable so(2,3) representation. We show that the orthosymplectic algebra osp(1|4) is the spectrum generating algebra for the Landau problem and, hence, for the 2D isotropic harmonic oscillator. The 2D harmonic oscillator is in duality with the 2D quantum Coulomb-Kepler systems, with the osp(1|4) symmetry broken down to the conformal symmetry so(2,3). The even so(2,3) submodule (coined Rac) generated from the ground state of zero angular momentum is identified with the Hilbert space of a 2D hydrogen atom. An odd element of the superalgebra osp(1|4) creates a pseudo-vacuum with intrinsic angular momentum 1/2 from the vacuum. The odd so(2,3)-submodule (coined Di) built upon the pseudo-vacuum is the Hilbert space of a magnetized 2D hydrogen atom: a quantum system of a dyon and an electron. Thus, the Hilbert space of the Landau problem is a direct sum of two massless unitary so(2,3) representations, namely, the Di and Rac singletons introduced by Flato and Fronsdal.Publication Metadata only Fundamentals and applications of heat currents in quantum systems(Springer Science and Business Media Deutschland GmbH, 2024) Department of Physics; Naseem, Muhammad Tahir; Müstecaplıoğlu, Özgür Esat; Department of Physics; College of Sciences; Graduate School of Sciences and EngineeringThe growing field of quantum thermodynamics has attracted much attention in the last two decades. The possibility of exploiting quantum features in thermal machines led to exciting avenues both from fundamental and application perspectives. For instance, in the presence of non-thermal baths, a quantum heat engine may surpass the classical Carnot limit. On the other hand, heat flow puts severe restrictions on the miniaturization of technologies based on quantum features. It is of paramount importance to look for efficient methods of heat management in the quantum system. One promising direction can be employing heat for powering these devices rather than considering the heat flow as noise. In this chapter, we briefly overview such strategies proposed for efficient heat flow management in the recent past. In particular, we present some of the developments in quantum thermal diodes, thermal transistors, and quantum thermal entanglement machines. In addition, some discussion on the particular models of quantum heat engines and quantum absorption refrigerators is presented. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Publication Metadata only Phase behaviour and dynamics of three-dimensional active dumbbell systems(Royal Society of Chemistry, 2024) Caporusso, C.B.; Negro, G.; Suma, A.; Digregorio, P.; Gonnella G; Cugliandolo, L.F.; Department of Physics; Carenza, Livio Nicola; Department of Physics; College of SciencesWe present a comprehensive numerical study of the phase behavior and dynamics of a three-dimensional active dumbbell system with attractive interactions. We demonstrate that attraction is essential for the system to exhibit nontrivial phases. We construct a detailed phase diagram by exploring the effects of the system's activity, density, and attraction strength. We identify several distinct phases, including a disordered, a gel, and a completely phase-separated phase. Additionally, we discover a novel dynamical phase, that we name percolating network, which is characterized by the presence of a spanning network of connected dumbbells. In the phase-separated phase we characterize numerically and describe analytically the helical motion of the dense cluster.