El grupo de Termodinámica y Computación Cuántica les invita al siguiente seminario Fecha: Viernes 5/4/2024 Hora: 11:00 am Lugar: Laboratorio de Fïsica Computacional, Dept de Electromagnetismo y Física de al Materia, Planta Baja, Facultad de Ciencias (junto al péndulo gigante) Ponente: Simon Morelli (Basque Centre for Applied Mathematics) Titulo: Correlation constraints and the Bloch geometry of two qubits Resumen: The quantum marginal problem investigates the compatibility of the eigenvalues of the local and global states of a multipartite quantum system. It is a fundamental problem in quantum information for which the solution is only known for simple cases. We investigate a simpler question of the same flavour: Given the purities of the local states of a multipartite system, what is the maximum purity the global state can achieve? We derive a new inequality that holds for bipartite systems of arbitrary dimensions and gives a complete solution for two qubits. Together with previous findings, this result gives rise to a new representation of the quantum state space – the Bloch ball – of two qubits. We show that this 3-dimensional visualization has various interesting properties regarding geometry and argue why it indeed captures many relevant properties of the full, high-dimensional, state space. Finally we extend this solution to three-qubit states, where we derive tight inequalities on the two- and three-body correlations compatible with a pure state. El seminario es accesible para los estudiantes de grado, a los que recomendamos encarecidamente que asistan. Para aquellos que no puedan asistir, también hemos configurado una reunión de Google donde el seminario se transmitirá en vivo. https://meet.google.com/pfu-awyh-hmz También os recordamos a todos la página web del Seminario de Grupos, https://ic1.ugr.es/eventos/wp/qjc/ donde se publicarán anuncios pasados, presentes y futuros. Nos vemos a todos allí DJM ________________________________________________________________________________ Dear all The Quantum Thermodynamics and Computation group cordially invites you to the following seminar Date: Friday 5/4/2024 Time: 11:00 am Location: Computational Physics Laboratory, Department of Electromagnetism and Condensed Mater, Ground Floor, Faculty of Science (next to the giant pendulum) Speaker: Simon Morelli (Basque Centre for Applied Mathematics) Title: Correlation constraints and the Bloch geometry of two qubits Abstract: The quantum marginal problem investigates the compatibility of the eigenvalues of the local and global states of a multipartite quantum system. It is a fundamental problem in quantum information for which the solution is only known for simple cases. We investigate a simpler question of the same flavour: Given the purities of the local states of a multipartite system, what is the maximum purity the global state can achieve? We derive a new inequality that holds for bipartite systems of arbitrary dimensions and gives a complete solution for two qubits. Together with previous findings, this result gives rise to a new representation of the quantum state space – the Bloch ball – of two qubits. We show that this 3-dimensional visualization has various interesting properties regarding geometry and argue why it indeed captures many relevant properties of the full, high-dimensional, state space. Finally we extend this solution to three-qubit states, where we derive tight inequalities on the two- and three-body correlations compatible with a pure state. The seminar is accessible to undergraduate students, whom we strongly encourage to attend. For those of you unable to attend the seminar, we have set-up the following google meet link for the upcoming seminar. https://meet.google.com/pfu-awyh-hmz We would also like to bring to your attention the groups seminar page 
 
https://ic1.ugr.es/eventos/wp/qjc/
 
where https://ic1.ugr.es/eventos/wp/qjc/%E2%80%A8%C2%A0%E2%80%A8where you can find relevant material and information about past, present, and future seminars. See you all there DJM. --------------------------------------------------------- Dr. Michalis Skotiniotis Grupo de Termodinámica y Información Cuántica. Departamento de Electromagnetismo y Física de la Materia. Instituto Carlos I de Física Teórica y Computacional. Facultad de Ciencias, Av. Fuentenueva s/n Universidad de Granada Granada, 18071 Spain Email: mskotiniotis@onsager.ugr.es ---------------------------------------------------------