Conferencia: «Quantum circuit complexity for light polarisation, or complexity with no complex numbers»

Seminario impartido por Jean-Pierre Gazeau, APC, Université Paris-Cité.

Abstract: I will present a form of quantum circuit complexity that extends to open systems. To illustrate the methodology, I focus on a basic model where the projective Hilbert space of states is depicted by the set of orientations in the Euclidean plane. Specifically, the investigation is about the dynamics of mixed quantum states as they undergo interactions with a sequence of gates. The approach involves the analysis of sequences of real 2X2 density matrices. This mathematical model is physically exemplified by the Stokes density matrices, which delineate the linear polarisation of a quasi-monochromatic light beam, and the gates, which are polarisers. The interaction polariser-linearly polarised light is construed as a quantum measurement. Each density matrix evolves within the framework of a Gorini-Kossakowski-Lindblad-Sudarshan (GKLS) process during the time interval between consecutive gates. Notably, when considering an upper limit for the cost function, the optimal number of gates follows a power-law relationship.

• Fecha: Martes, 14 de mayo de 2024
• Lugar: Salón de Grados de la Facultad de Ciencias
• Horario: 12:00h.
• Organiza: Máster FisyMat
• Más información: calixto@ugr.es