Measurement-Based Control for Minimizing Energy Functions in Quantum Systems

In variational quantum algorithms (VQAs), the most common objective is to find the minimum energy eigenstate of a given energy Hamiltonian. In this paper, we consider the general problem of finding a sufficient control Hamiltonian structure that, under a given feedback control law, ensures convergence to the minimum energy eigenstate of a given energy function. By including quantum non-demolition (QND) measurements in the loop, convergence to a pure state can be ensured from an arbitrary mixed initial state. Based on existing results on strict control Lyapunov functions, we formulate a semidefinite optimization problem, whose solution defines a non-unique control Hamiltonian, which is sufficient to ensure almost sure convergence to the minimum energy eigenstate under the given feedback law and the action of QND measurements. A numerical example is provided to showcase the proposed methodology.Comment: Accepted for IFAC 2023 - 22nd World Congress of the International Federation of Automatic Contro

Investigation of Physicochemical Properties, Antioxidant Activity and In vitro Bioaccessibility of Cornelian Cherry (Cornus mas. L.) Nectar Enriched

Cornelian cherry (Cornus mas L.) fruit is a member of the cranberry family, which contains many bioactive components. However, because of its bitter taste, the number of products it can be processed is limited. In this study, beverages were prepared by adding five different herbal teas (linden, sage, chamomile, green tea, artichoke peel) to cranberry nectar sweetened with apple juice concentrate. Brix, pH, antioxidant capacity, (DPPH, FRAP, CUPRAC), total phenolic content, total monomeric anthocyanin, color (L*, a*, b*, C*, h°) and in vitro bioaccessibility analyzes were performed in the beverages. Results of antioxidant capacity analysis were determined between 129.00±11.85 µmol TE/g DM- 365.42±2.62 µmol TE/g DM; 56.61±16.42 µmol TE/g DM – 103.39±2.36 µmol TE/g DM; 157.97±25.35 µmol TE/g DM – 276.82±22.81 µmol TE/g DM with DPPH, CUPRAC and FRAP methods, respectively. The total phenolic content was found between 655.35±24.17 mg GAE/100 g DM and 1165.09±30.69 mg GAE/100 g DM. The beverages containing green tea infusion (4.13±1.69 mg/kg) had the lowest total monomeric anthocyanin content, while beverages containing artichoke peel infusion (6.33±0.67 mg/kg) had the highest. In the samples analyzed after in vitro gastric digestion, an increase was observed in the total monomeric anthocyanin amount compared to the pre-digested samples, while a decrease was found in the antioxidant capacity and total phenolic content, in general. By adding herbal teas to cornelian cherry nectar, not only improved sensorial and nutritional properties of the fruit nectar, but also a new functional beverage was developed

Application of response surface methodology for optimisation of Cornelian cherry - Capia pepper leather dried in a heat pump drying system

The heat pump drying system was optimised for cornelian cherry-capia pepper leather production development using response surface methodology. The central composite design was used to optimise the process parameters in terms of drying time, coefficient of the performance of heat pump, coefficient of the performance of the whole system, specific moisture extracted ratio, energy consumption, drying rate and colour values. The optimal condition of independent variables was obtained as a cornelian cherry pulp concentration of 47.419% and drying temperature of 33.574°C with composite desirability of 0.846. Moreover, hydroxymethylfurfural (HMF) and effective moisture diffusivity (Deff) values of all runs were analysed. HMF was not determined in cornelian cherry-capia pepper leather. Deff values of cornelian cherry-capia pepper leather were between 1.026×10-9 - 1.532×10-9 m2s-1. The drying behaviour of cornelian cherry-capia pepper leather with optimal conditions acquired with the central composite design was evaluated with seven thin-layer drying models. The statistical parameters based on R2, root mean square of error and χ2 values were determined between 0.8267 to 0.9845, 0.004087 to 0.035626 and 0.000853 to 0.066247, respectively. Page and Modified Page models were assumed to represent the heat pump drying behaviour of the cornelian cherry-capia pepper leather in thin layers compared to the other models

Serum Magnezyum Düzeyi, Plazma Aterojenik İndeksi ve Glomerüler Filtrasyon Hızı Arasındaki İlişki

Amaç: Magnezyum, kardiyovasküler hastalıklar başta olmak üzere birçok kronik hastalıkla ilişkilendirilmektedir. Bu çalışmanın amacı, serum magnezyum düzeyi, plazma aterojenik indeksi (PAİ) ve glomerüler filtrasyon hızı (GFH) arasındaki ilişkinin değerlendirilmesidir. Gereç ve Yöntem: Çalışmaya dahil edilen 214 hastanın verileri retrospektif olarak incelendi. Tahmini GFH 60 mL/dakika/1,73 m2 ve üzerinde olanlar “yüksek GFH grubu”, 60 mL/dakika/1,73 m2 ’den düşük olanlar “düşük GFH grubu” olarak gruplandırıldı. Serum trigliserit düzeyinin serum yüksek yoğunluklu lipoprotein düzeyine oranının logaritması alınarak PAİ hesaplandı. Bulgular: yüksek GFH grubunda 72, düşük GFH grubunda 142 hasta yer aldı. Serum magnezyum düzeyi ve PAİ açısından gruplar arasında farklılık saptanmadı. Tüm popülasyonda serum magnezyum düzeyi ile ilişkili faktörler incelendiğinde, sadece PAİ ile magnezyum arasında negatif yönde bir ilişki saptandı [Odds ratio (OR): -0,212]. Yine tüm popülasyonda PAİ ile ilişkili faktörler incelendiğinde, PAİ ile serum magnezyum düzeyi arasında negatif (OR: -0,189); vücut kitle indeksi, sistolik kan basıncı ve serum ürik asit düzeyi arasında pozitif yönde bir ilişki saptandı (sırasıyla; OR: 0,154; 0,276; 0,165). Gerek PAİ, gerekse magnezyum düzeyleri ile tahmini glomerüler filtrasyon hızı arasında ilişki saptanmadı. Sonuç: Serum magnezyum düzeyi ile PAİ arasındaki ters yönlü ilişki, hipomagnezeminin aterojenite ile ilişkisine dair genel literatür bilgisi ile uyumludur. PAİ ve serum magnezyum düzeyi ile GFH arasında bir ilişkinin saptanmamış olması, hasta sayısının azlığına bağlanabilir

Influence of a hybrid drying combined with infrared and heat pump dryer on drying characteristics, colour, thermal imaging and bioaccessibility of phenolics and antioxidant capacity of mushroom slices

An infrared-assisted heat pump drying (IR-HPD) was designed and used for drying of mushroom slices at three different infrared (IR) powers (50, 100, and 150 W) and a fixed drying temperature of 40°C and air velocity of 1 m/s. The changes in total phenolic content (TPC), total antioxidant capacity (TAC) and individual phenolic contents bioaccessibility, drying characteristics, and colour values of mushroom slices were investigated. IR-HPD provided 13.11 to 30.77% higher energy savings than HPD and reduced drying time between 9.48 and 26.72%. Page, Modified Page models were considered the best for predicting the thin layer drying behaviour of mushroom slices. The effective moisture diffusivity (Deff) value increased with IR power and ranged between 6.491x10-10 and 9.023x10-10 m2s-1. The contents of TPC, TAC, and individual phenolics in mushroom slices were significantly reduced (p<0.05) after drying. In vitro the bioaccessibility of phenolic compounds and TAC generally decreased, whereas TPC bioaccessibility was increased. Colour values were decreased except for a* value that increased after drying. Thermal imaging results showed that IR lamps increase the temperature of the products in the middle close to the lamp by approximately 1.5°C. In addition, thermal imaging gave a better understanding and visualised the effect of different power IR lamps on the temperature distribution of the products according to their distance from the lamp. As a result, drying mushrooms with a hybrid drying system combined with IR and heat pump dryer provided higher energy savings than HPD, reduced drying time, and maintained the physical and nutritional characteristics of mushrooms. Overall, the use of IR-HPD is an alternative tool that allows us to obtain high-quality dried mushrooms with good nutritional attributes and a high amount of bioaccessible polyphenols

Heteroclinic Ratchets in a System of Four Coupled Oscillators

We study an unusual but robust phenomenon that appears in an example system of four coupled phase oscillators. We show that the system can have a robust attractor that responds to a specific detuning between certain pairs of the oscillators by a breaking of phase locking for arbitrary positive detunings but not for negative detunings. As the dynamical mechanism behind this is a particular type of heteroclinic network, we call this a 'heteroclinic ratchet' because of its dynamical resemblance to a mechanical ratchet

The Analysis Of The Stability Of Switched Linear Systems

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2007Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2007Bu çalışmada, bir altsistemler ailesinden ve bu altsistemler arasındaki geçişleri yöneten bir anahtarlama kuralından oluşan anahtarlanmış sistemler genel olarak incelenmiş; ve altsistemler ailesinin her bir üyesinin doğrusal olduğu durumda oluşan anahtarlanmış doğrusal sistemlerin kararlılığına ilişkin literatürde bulunan üç temel problem tanıtılmıştır. Bunlardan keyfi anahtarlama problemi olarak adlandırdığımız birinci problemde anahtarlama işareti ne olursa olsun sistemin kararlı olmasının koşullarını aranır. Kararlılaştırma problemi olarak adlandığımız ikinci problemde ise verilmiş bir altsistemler ailesini kararlı kılan bir anahtarlama işaretinin varlığı ve ne olduğu araştırılır. Çalışmamızda bu iki probleme ilişkin birincisinde ortak Lyapunov fonksiyonu bulunmasına ikincisinde ise altsistemlere ilişkin matrislerin bir Hurwitz konveks kombinasyonunun bulunmasına dayanan literatürde bulunan iki çözüm anlatılmıştır. Uygun anahtarlama işaretleri kümesini bulma problemi olarak adlandırdığımız üçüncü problem ise verilmiş bir altsistemler ailesini kararlı kılan özel anahtarlama işaretleri kümelerini bulma problemidir. Bu probleme ilişkin kendi geliştirdiğimiz bir yaklaşım sunulmuştur. Anahtarlanmış sistemlerin iteratif fonksiyonlar sistemlerine dönüştürülmesine dayanan bu yaklaşım ile anahtarlanmış sistemin kararlı olması için anahtarlama işaretindeki sabit aralıkların minimum uzunluğunun belli bir değerden büyük olmasına dayanan bir yeter koşul verilmiştir. Son olarak elde ettiğimiz sonuçlar iki örnek üzerinden değerlendirilmiş ve elde edilen sonuçların bu konuyla ilgili yapacağımız ileriki çalışmalar konusunda işaret ettiği yönler tartışılmıştır. Özellikle altsistemlere ilişkin matrislerin özvektörlerinin yakınlığına dayalı bir açıklama ile uygun anahtarlama kümesini bulma problemine ilişkin bir çözüm yoluna işaret edilmiştir.In this study, switched systems, which consist of a family of subsystems and a switching rule that controls the switching between the subsystems, are explained generally, and the three problems founded in literature on the stability of switched linear systems, which arise in the case that all the subsystems are linear, are introduced. Among these, the first one called the arbitrary switching problem deals with finding the conditions that results in the stability of the switched system independent of the switching signal. The second one called the stabilizing problem considers how to find a stabilizing switching signal for a given family of subsystems. In the thesis we explained the two approaches to find the solution of these problems which depends on the presence of common Lyapunov function for the former, and on finding a Hurwitz convex combination of the subsystem matrices for the latter. The third problem that we called the problem of finding the proper set of switching signals concerns with some special sets of switching signals forming a stable switched system for a given family of subsystems. We presented our own approach to solve this problem. By the approach of converting a switched system to an equivalent iterated function system, a sufficient condition is presented based on the minimum length of the intervals where the switching signal is constant. Finally, we discuss on some issues for future research that the study points out.Yüksek LisansM.Sc