Thursday, September 25, 2025 15:00 MLIT Room 310 Seminar of the scientific department of computational physics Seminar program: M.V. Babich (PDMI RAS), L. Bordag, A.M. Khvedelidze, D. Mladenov (Bulgaria, Sofia University) On Mathematical Problems of Error Suppression in Single-Qubit Gates Abstract: A central challenge in building quantum computers is realising logical gates that remain stable under unavoidable systematic errors caused by external noise and experimental imperfections. One promising strategy is to replace a single gate with a tailored composite sequence of single-qubit operations. We present an algorithm for constructing such sequences using two types of single-qubit gates. The approach relies on Lie group theory and spherical geometry, formulating the task as approximating an element of SU(2) by a product of N elements from two one-parameter subgroups. The optimisation criterion is the gate fidelity expressed through the corresponding N Euler angles. As a case study, we demonstrate the method with a six-gate sequence, highlighting its potential for systematic error suppression in practical implementations. V.V. Kornyak Do Quantum States Have to Be Continuous? Galois Fields and Multiparticle Quantum Systems Abstract: The use of infinities in standard quantum mechanics leads to inconsistencies and unphysical artifacts. Replacing the infinite elements in quantum theory with finite structures that arise naturally within the phase-space formulation of quantum mechanics eliminates the issues generated by infinities while reproducing all the results of traditional quantum mechanics. In this approach, Galois fields are a natural means of describing systems of indistinguishable particles. We discuss computational aspects of studying the dynamics of quantum systems over Galois fields. Information about the seminar at Indico.
