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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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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 Low-temperature quantum thermometry boosted by coherence generation(American Physical Society, 2023) ; Department of Physics; Ullah, Asghar; Naseem, Muhammad Tahir; Müstecaplıoğlu, Özgür Esat; Department of Physics; ; Graduate School of Sciences and Engineering; College of Sciences;The precise measurement of low temperatures is significant for both the fundamental understanding of physical processes and technological applications. In this work, we present a method for low-temperature measurement that improves thermal range and sensitivity by generating quantum coherence in a thermometer probe. Typically, in temperature measurements, the probes thermalize with the sample being measured. However, we use a two-level quantum system, or qubit, as our probe and prevent direct probe access to the sample by introducing a set of ancilla qubits as an interface. We describe the open system dynamics of the probe using a global master equation and demonstrate that while the ancilla-probe system thermalizes with the sample, the probe per se evolves into a nonthermal steady state due to nonlocal dissipation channels. The populations and coherences of this steady state depend on the sample temperature, allowing for precise and wide-range low-temperature estimation. We characterize the thermometric performance of the method using quantum Fisher information and show that the quantum Fisher information can exhibit multiple and higher peaks at different low temperatures with increasing quantum coherence and the number of ancilla qubits. Our analysis reveals that the proposed approach, using a nonthermal qubit thermometer probe with temperature-dependent quantum coherence generated by a multiple qubit interface between a thermal sample and the probe qubit, can enhance the sensitivity of temperature estimation and broaden the measurable low-temperature range. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Publication Metadata only High-throughput computational screening of MOF adsorbents for efficient propane capture from air and natural gas mixtures(AIP Publishing, 2024) Department of Chemical and Biological Engineering; Erçakır, Göktuğ; Aksu, Gökhan Önder; Keskin, Seda; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; College of EngineeringIn this study, we used a high-throughput computational screening approach to examine the potential of metal-organic frameworks (MOFs) for capturing propane (C3H8) from different gas mixtures. We focused on Quantum MOF (QMOF) database composed of both synthesized and hypothetical MOFs and performed Grand Canonical Monte Carlo (GCMC) simulations to compute C3H8/N2/O2/Ar and C3H8/C2H6/CH4 mixture adsorption properties of MOFs. The separation of C3H8 from air mixture and the simultaneous separation of C3H8 and C2H6 from CH4 were studied for six different adsorption-based processes at various temperatures and pressures, including vacuum-swing adsorption (VSA), pressure-swing adsorption (PSA), vacuum-temperature swing adsorption (VTSA), and pressure-temperature swing adsorption (PTSA). The results of molecular simulations were used to evaluate the MOF adsorbents and the type of separation processes based on selectivity, working capacity, adsorbent performance score, and regenerability. Our results showed that VTSA is the most effective process since many MOFs offer high regenerability (>90%) combined with high C3H8 selectivity (>7 x 103) and high C2H6 + C3H8 selectivity (>100) for C3H8 capture from air and natural gas mixtures, respectively. Analysis of the top MOFs revealed that materials with narrow pores (<10 angstrom) and low porosities (<0.7), having aromatic ring linkers, alumina or zinc metal nodes, typically exhibit a superior C3H8 separation performance. The top MOFs were shown to outperform commercial zeolite, MFI for C3H8 capture from air, and several well-known MOFs for C3H8 capture from natural gas stream. These results will direct the experimental efforts to the most efficient C3H8 capture processes by providing key molecular insights into selecting the most useful adsorbents.Publication Metadata only PhysioPatch: a multimodal and adaptable wearable patch for cardiovascular and cardiopulmonary assessment(IEEE-Inst Electrical Electronics Engineers Inc, 2024) ; Department of Electrical and Electronics Engineering; Hayırlıoğlu, Yusuf Ziya; Gürsoy, Beren Semiz; Department of Electrical and Electronics Engineering; ; Graduate School of Sciences and Engineering; College of Engineering;Remote monitoring systems offer significant advantages in assessing cardiovascular and cardiopulmonary health, facilitating early diagnosis and enabling personalized treatment plans. In this article, we present a novel wearable patch, PhysioPatch, which could facilitate comprehensive monitoring of cardiovascular and cardiopulmonary functions by simultaneously capturing various physiological signals, including electrocardiogram (ECG), seismocardiogram (SCG), photoplethysmogram (PPG), and body temperature. The design comprises a main body intended for placement on the mid-sternum and a detachable daughter body, enabling distal measurements to enhance comprehensive assessment. While the main body includes the sensors for measuring the body temperature, ECG, proximal PPG and SCG signals, and other electronics such as the microcontroller, the battery, the battery management system (BMS), the Bluetooth, and the microSD card;the daughter body houses the sensors for distal pulse vibration and PPG signal acquisition. Along with the system design, the algorithms to derive various hemodynamic parameters (heart rate (HR), HR variability (HRV), respiration rate, and oxygen saturation) are also presented. The system was validated with a human subject study including 20 participants, and the results have revealed that the PhysioPatch is capable of achieving high-quality signals, resulting in accurate derivation of hemodynamic parameters. Overall, such a system could potentially offer continuous health monitoring outside clinical settings, regardless of time and environmental stressors.Publication Metadata only Conditions on detecting tripartite entangled state in psychophysical experiments(SPRINGER HEIDELBERG, 2024) Department of Physics; Gassab, Lea; Pedram, Ali; Müstecaplıoğlu, Özgür Esat; Department of Physics; Graduate School of Sciences and Engineering; College of SciencesThis paper explores the sensitivity of the human visual system to quantum entangled light. We examine the possibility of human subjects perceiving multipartite entangled state through psychophysical experiments. Our focus begins with a bipartite entangled state to make a comparative study with the literature by taking into account additive noise for false positive on bipartite entanglement perception by humans. After that, we limit our similar investigation to a tripartite entangled state for simplicity in higher dimensions. To model the photodetection by humans, we employ the probability of seeing determined for coherently amplified photons in Fock number states, including an additive noise. Our results indicate that detecting bipartite and tripartite entanglement with the human eye is possible for a certain range of additive noise levels and visual thresholds. Finally, we discuss several alternative amplification methods.Publication Metadata only What is quantum in probabilistic explanations of the sure-thing principle violation?(Elsevier Ireland Ltd, 2024) Department of Physics; Mahalli, Nematollah Farhadi; Pusuluk, Orhan; Department of Physics; College of SciencesThe Prisoner's Dilemma game (PDG) is one of the simple test-beds for the probabilistic nature of the human decision-making process. Behavioral experiments have been conducted on this game for decades and show a violation of the so-called sure-thing principle, a key principle in the rational theory of decision. Quantum probabilistic models can explain this violation as a second-order interference effect, which cannot be accounted for by classical probability theory. Here, we adopt the framework of generalized probabilistic theories and approach this explanation from the viewpoint of quantum information theory to identify the source of the interference. In particular, we reformulate one of the existing quantum probabilistic models using density matrix formalism and consider different amounts of classical and quantum uncertainties for one player's prediction about another player's action in PDG. This enables us to demonstrate that what makes possible the explanation of the violation is the presence of quantum coherence in the player's initial prediction and its conversion to probabilities during the dynamics. Moreover, we discuss the role of other quantum information-theoretical quantities, such as quantum entanglement, in the decision-making process. Finally, we propose a three-choice extension of the PDG to compare the predictive powers of quantum probability theory and a more general probabilistic theory that includes it as a particular case and exhibits third-order interference. © 2024 Elsevier B.V.Publication Metadata only Fundamental transfer matrix for electromagnetic waves, scattering by a planar collection of point scatterers, and anti- PT -symmetry(American Physical Society, 2023) Loran, Farhang; Department of Mathematics; Mostafazadeh, Ali; Faculty Member; Department of Mathematics; College of Sciences; 4231We develop a fundamental transfer-matrix formulation of the scattering of electromagnetic (EM) waves that incorporates the contribution of the evanescent waves and applies to general stationary linear media which need not be isotropic, homogenous, or passive. Unlike the traditional transfer matrices whose definition involves slicing the medium, the fundamental transfer matrix is a linear operator acting in an infinite-dimensional function space. It is given in terms of the evolution operator for a nonunitary quantum system and has the benefit of allowing for analytic calculations. In this respect it is the only available alternative to the standard Green's-function approaches to EM scattering. We use it to offer an exact solution of the outstanding EM scattering problem for an arbitrary finite collection of possibly anisotropic nonmagnetic point scatterers lying on a plane. In particular, we provide a comprehensive treatment of doublets consisting of pairs of isotropic point scatterers and study their spectral singularities. We show that identical and PT-symmetric doublets do not admit spectral singularities and cannot function as a laser unless the real part of their permittivity equals that of the vacuum. This restriction does not apply to doublets displaying anti-PT-symmetry. We determine the lasing threshold for a generic anti-PT-symmetric doublet and show that it possesses a continuous lasing spectrum.Publication Metadata only Rate-delay tradeoff with network coding in molecular nanonetworks(IEEE-Inst Electrical Electronics Engineers Inc, 2013) N/A; N/A; Department of Electrical and Electronics Engineering; Ünlütürk, Bige Deniz; Malak, Derya; Akan, Özgür Barış; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 6647Molecular communication is a novel nanoscale communication paradigm, in which information is encoded in messenger molecules for transmission and reception. However, molecular communication is unreliable and has highly varying long propagation delays mainly due to the stochastic behavior of the freely diffusing molecules. Thus, it is essential to analyze its delay characteristics, as well as the tradeoff between the rate and delay, in order to reveal the capabilities and limitations of molecular information transmission in nanonetworks. In this paper, first, a new messenger-based molecular communication model, which includes a nanotransmitter sending information to a nanoreceiver, is introduced. The information is encoded on a polyethylene molecule, CH3(CHX)(n)CH2F, where X stands for H and F atoms representing 0 and 1 bits, respectively. The emission of the molecules is modeled by puffing process which is inspired by the alarm pheromone release by animals in dangerous situations. In this work, the rate-delay characteristics of this messenger-based molecular communication model are explored. Then, a Nano-Relay is inserted in the model, which XOR's the incoming messages from two different nanomachines. Performance evaluation shows that indeed, a simple network coding mechanism significantly improves the rate given delay of the system, and vice versa.Publication Metadata only Polar solvent-free room temperature synthesis of CsPbX3 (X = Br, Cl) perovskite nanocubes(Royal Society of Chemistry, 2023) Güvenç, C. Meriç; Balcı, Sinan; Department of Physics; Kocabaş, Aşkın; Faculty Member; Department of Physics; College of Sciences; 227753Conventionally, colloidal lead halide perovskite nanocubes have been synthesized by the hot-injection or ligand-assisted reprecipitation (LARP) methods. We herein demonstrate a polar solvent-free room temperature method for the synthesis of CsPbX3 (X = Br, Cl) nanocubes. In addition to the commonly used ligand pair of oleylamine and oleic acid, guanidinium (GA) has been used to passivate the surface of the nanocrystals. Our study demonstrates that GA inhibits the formation of low dimensional structures such as nanowires and nanoplatelets and further supports the formation of perovskite nanocubes. In fact, GA diminishes the restricted monomer-addition effect of long-chain oleylammonium (OLAM) ions to the nanocrystal. We show that above a critical GA/OLAM molar ratio, the synthesis yields homogeneous CsPbX3 (X = Br, Cl) nanocubes. Importantly, we observe the nucleation and growth kinetics of the GA-assisted CsPbBr3 nanocube formation by using in situ absorption and photoluminescence (PL) measurements. Small nanocrystals with an excitonic absorption peak at around 435 nm and photoluminescence (PL) maxima at 447 nm were nucleated and continuously shifted to longer wavelengths during the growth period. Crucially, our method allows the synthesis of CsPbCl3 nanocubes at room temperature without using polar organic solvents. The synthesized CsPbBr3, CsPb(Cl0.5Br0.5)3, and CsPbCl3 nanocubes have PL peaks at 508 nm, 443 nm, and 405 nm, photoluminescence quantum yields (PLQY) of 85%, 58% and 5%, and lifetimes of 18.98 ns, 18.97 ns, and 14.74 ns, respectively.Publication Metadata only Point interactions, metamaterials, and PT-symmetry(Academic Press Inc Elsevier Science, 2016) NA; Department of Mathematics; Mostafazadeh, Ali; Faculty Member; Department of Mathematics; College of Sciences; 4231We express the boundary conditions for TE and TM waves at the interfaces of an infinite planar slab of homogeneous metamaterial as certain point interactions and use them to compute the transfer matrix of the system, This allows us to demonstrate the omnidirectional reflectionlessness of Veselago's slab for waves of arbitrary wavelength, reveal the translational and reflection symmetry of this slab, explore the laser threshold condition and coherent perfect absorption for active negative-index metamaterials, introduce a point interaction modeling phase-conjugation, determine the corresponding antilinear transfer matrix, and offer a simple proof of the equivalence of Veselago's slab with a pair of parallel phase-conjugating plates. We also study the connection between certain optical setups involving metamaterials and a class of PT-symmetric quantum systems defined on wedge-shape contours in the complex plane. This provides a physical interpretation for the latter.