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Modelling optimal implementation of an arbitrary N-qubit quantum gate within the generalized Bloch vectors formalism
Quantum Information Processing. 2026. Vol. 25. Article 358.
The optimal implementation of quantum gates for closed $N$-qubit systems is one of the key challenges for practical realization of many quantum information processing tasks. In the present article, based on the generalized Bloch vectors formalism [J. Phys. A: Math. Theor. 54, 195301 (2021)] for a finite-dimensional quantum system, we develop a new \emph{general} model for the optimal implementation of quantum gates, which is formulated in terms of the Bloch vectors for the unitary evolution operator and the system Hamiltonians, drift and control, and has the \textcolor{red}{unified mathematical form, which is standard for the mathematical control theory and applicable} for the implementation of an arbitrary N-qubit gate within any closed N-qubit system, satisfying the controllability conditions. Within the developed optimal model, the cost functional has both the terminal part and also, the integral part with the special scaling, and this allows us to specify the quantum optimal control synthesis via solving the two-point boundary value problem (BVP) for the system of ordinary differential equations (ODEs), which can be explored numerically by any of the known BVP solvers for ODEs. The numerical experiments, conducted for the implementation within the developed optimal model of a variety of N=1,2,3 qubit gates, demonstrate the high accuracy of the model-based results.
Ермолаев Е. С., Chernyshev V. L., Skripchenko A., Journal of Nonlinear Science 2026 Vol. 36 No. 122 (2026) P. 1–37
We study upper bounds for the moment of permanent -saturation in finite metric graphs. The dynamics is generated by moving points travelling with unit speed along edges and branching into all outgoing directions whenever they reach a vertex. We first reformulate this branched dynamics in terms of birth times at vertices and prove a sufficient ...
Added: November 12, 2026
Alfimov Mikhail, Kurakin Andrey, Journal of High Energy Physics 2026 Vol. 2026 Article 99
We continue studying regularization scheme dependence of the 𝒩 = 2 supersymmetric sigma models. In the present work the previous result for the four loop β-function is extended to the five loop order. Namely, we find the renormalization scheme, in which the fifth loop contribution is completely eliminated, while the fourth loop contribution is represented ...
Added: November 12, 2026
Малюкова П. А., Baksheeva K., Рудаков К. И. et al., Письма в Журнал технической физики 2026 Т. 52 № 23 С. 27–30
This paper presents the results of a study on human skin emission under mental stress at a frequency of 247 GHz. An experimental setup based on a receiver utilizing a superconductor-insulator-superconductor (SIS) junction was developed. The study was conducted with 22 volunteers aged 18 to 73. The correlation between the SIS-junction-based detector and a galvanic ...
Added: November 12, 2026
Baksheeva K., Zhurin Y., Ozhegov R. et al., Письма в Журнал технической физики 2026 Т. 52 № 23 С. 19–22
This paper presents a study on the characteristics of terahertz (THz) emission from human skin under mental stress. The research was conducted using a single-pixel THz camera based on a superconducting integrated receiver. The resulting brightness-temperature images revealed localized spikes in the area of the bridge of the nose and the brow ridges, which may ...
Added: November 12, 2026
Ignatev M., Vilkin T., Mediterranean Journal of Mathematics 2026 Vol. 23 No. 2 Article 70
Trinomial varieties are affine varieties given by a system of equations consisting of polynomials with three terms. Such varieties are total coordinate spaces of normal varieties with torus action of complexity one. For an affine variety X, we consider the subgroup SAut(X) of the automorphism group generated by all algebraic subgroups isomorphic to the additive ...
Added: November 12, 2026
Maksaev A., Promyslov V., Тишутин П. С., Записки научных семинаров ПОМИ РАН 2026 Т. 554 С. 218–235
Let K be an algebraically closed field and let ℰₖ be the set of n × n matrices over K with exactly k distinct eigenvalues. Previously, the classification of linear maps T: Mₙ(K) → Mₙ(K) satisfying T(ℰₙ) ⊆ ℰₙ was obtained for invertible maps over fields of characteristic 0. In this paper, the classification is ...
Added: November 11, 2026
Budkov Y., The European Physical Journal E - Soft Matter 2026 Vol. 49 No. 105
We calculate fluctuation-induced contributions to the shear and configurational bulk viscosities arising from Korteweg stresses in a Gaussian scalar-field theory. Starting from the Ginzburg--Landau functional, we derive the stress tensor and examine its gauge freedom. The longitudinal stress is then subjected to the Mori projection. In
the symmetric Gaussian phase the projection onto the order-parameter zero ...
Added: November 11, 2026
Barinova M., Tirskaya Karina, Владикавказский математический журнал 2026 Vol. 28 No. 3 P. 25–43
In this paper, the problem of the existence of an energy function for discrete dynamical systems defined by structurally stable diffeomorphisms is studied. For the considered class of dynamical systems, such a function is defined as a continuous function that decreases along the orbits of the system outside the non-wandering set and remains constant on ...
Added: November 11, 2026
Illarionov A., Математический сборник 2026 Т. 217 № 11 С. 56–87
Let $b(\alpha;T)$ be the number of best simultaneous Diophantine approximations with common denominator $\le T$ to the point $\alpha \in {\Bbb R}^n$. We derive asymptotic formulas for the mean value of this quantity (averaging is performed over all rational points of the form $\alpha = (k_1/N,\ldots, k_n/N)$, $N\le R$), as well as for its mathematical ...
Added: November 10, 2026
Minaev V., Измерительная техника 2026 Т. 75 № 5 С. 54–65
Для высокоточного контроля формы поверхностей оптических деталей применяют интерферометры Физо. Интерферометры Физо с общим путём используют для измерений такого параметра, как отклонение от плоскостности и сферичности (максимального размаха) PV (peak-valley), так как данная конструкция предотвращает влияние аберраций оптической системы на результаты измерений. При настройке интерферометра Физо на нулевую полосу, когда опорный и предметный пучки проходят ...
Added: November 10, 2026
Minaev V., Оптический журнал 2026 Т. 93 № 10 С. 43–52
Предмет исследования. Метод абсолютной калибровки интерференционного микроскопа с использованием поверхности жидкости в качестве эталонной плоскости. Цель работы. Повышение точности измерений профиля поверхности оптических деталей с помощью интерференционного микроскопа за счёт коррекции аберраций оптической системы с использованием жидкого эталонного зеркала. Метод. Метод двух экспозиций с вычитанием фазовых изображений эталонной поверхности. Сравнение результатов измерений высоты ступеньки с использованием жидкого зеркала в качестве ...
Added: November 10, 2026
Minaev V., Оптический журнал 2026 Т. 93 № 10 С. 31–42
Предмет исследования. Интерференционный метод измерений отклонений от плоскостности оптических поверхностей крупногабаритных плоских оптических элементов на базе интерферометра «PhSh-Лямбда» и оценка эффективности алгоритмов обработки интерферограмм в условиях вибрационных и воздушных возмущений. Цель работы. Расширение возможностей интерферометра «PhSh-Лямбда» путём использования его в качестве базового приёмно-передающего блока для широкоапартурного неравноплечного интерферометра Тваймана–Грина при контроле крупногабаритных плоских оптических элементов диаметром до 600 мм. ...
Added: November 10, 2026
Minaev V., Оптика и спектроскопия 2026 Т. 134 № 11 С. 1382–1390
Исследованы методы восстановления фазового распределения из интерферограмм при контроле формы и топографии поверхностей оптических элементов с целью разработки подхода, позволяющего выполнять реконструкцию фазы методом фазовых шагов по одной интерферограмме в полосах конечной ширины. Для этого, используя метод Фурье, вначале синтезируется набор сдвинутых по фазе интерферограмм, по которым с помощью метода фазовых шагов восстанавливается фазовое распределение. ...
Added: November 10, 2026
Alexey A. Sokolik, Azat F. Aminov, Vdovin E. et al., Applied Physics Letters 2026 Vol. 129 No. 16 P. 1–6
Electron tunneling between sheets of bilayer Bernal graphene twisted at different small angles was studied experimentally and theoretically. The current-voltage characteristics exhibit resonant peaks, steps, and regions of negative differential resistance, the origin of which is explained by the intersections of energy- and momentum-shifted electron dispersions of adjacent layers. A theoretical analysis of tunneling transport ...
Added: November 10, 2026
Vereshchagin N., Математический сборник 2026 Т. 217 № 10 С. 3–46
Теорема Гудмана-Штрауса утверждает, что для “почти всякой” подстановки семейство подстановочных замощений софично, т.е. может быть задано локальными правилами для некоторой раскраски плиток. Условия на подстановку, гарантирующие софичность, довольно сложные.
В настоящей работе мы предлагаем версию теоремы Гудмана-Штрауса с более простыми условиями на подстановку. Хотя эти условия достаточно ограничительны, мы показываем, что в сочетании с двумя простыми приемами (взятием достаточно ...
Added: November 10, 2026
Guskov T., Gerke K., Kondratyuk N. et al., Molecular Simulation 2026 Vol. 52 No. 7 P. 546 – 555
Equilibration is often assumed rather than tested in molecular dynamics studies of confined liquid–liquid interfaces, even though different physical properties may relax on different time scales. In this work, equilibration is examined using an automated truncation method based on the marginal standard error rule. Interfacial geometry, wetting behaviour, and density-related properties are analysed for liquid–liquid ...
Added: November 10, 2026
Lukyanchuk V., Norman G., Kondratyuk N. et al., Scientific Reports 2026 Vol. 16 No. 1 Article 16435
Previously, it has been effectively shown that nuclear quantum effects (NQE) considerably influence the prediction of the warm dense hydrogen phase diagram. Here, we study the influence of NQE on the parameters of the conducting state formation in warm dense hydrogen using path integral molecular dynamics (PIMD) within the framework of the finite temperature density ...
Added: November 10, 2026
Zhurin Y., Baksheeva K., Ozhegov R. et al., Цифровая обработка сигналов 2026 № 3 С. 24–29
This paper presents a software tool developed for processing terahertz thermal images of the human face acquired during a controlled psychophysiological experiment. In the experiment, a 500 GHz single-pixel detector combined with a two-mirror scanning system forms a sequence of low-resolution thermal frames (700×51 pixels) of the subject’s face while the person undergoes relaxation and ...
Added: November 9, 2026
Abumusabh M., Adachi I., Adamczyk K. et al., Physical Review Letters 2026 Vol. 137 No. 19 Article 191901
We study the processes e+e− → Υ_J(1D)η and e+e− → Υ_J(1D)π+π− at center-of-mass energies √s=(10.73 – 11.02) GeV using a 142.5 fb−1 data sample, including 122 fb−1 near the Υ(10860) peak (√s = 10.866 GeV), collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. From the peak sample, the products of Born cross ...
Added: November 9, 2026