The 2023 Salam Distinguished Lecture Series will feature theoretical physicist Sandu Popescu, professor of physics at the University of Bristol, UK. Popescu will deliver three lectures on topics related to the fundamental aspects of quantum physics. The three lectures will take place from 25 to 27 January in ICTP's Budinich Lecture Hall. Professor Popescu's main field of research centres on the conceptual and fundamental aspects of quantum physics. He is a pioneer of quantum information, best known for his work on entanglement and the associated phenomenon of non-locality, which are crucial for our current understanding of quantum theory. He has also worked on many other aspects of quantum theory, ranging from the very fundamental, to designing practical experiments (such as the first quantum teleportation experiment), to patentable commercial applications. The first Lecture on Wednesday 25 January 2023 at 16.00 hrs will be on "The smallest possible thermal machines and the foundations of thermodynamics". ABSTRACT: Popescu will raise the question on the fundamental limits to the size of thermal machines – refrigerators, heat pumps and work producing engines - and will present the smallest possible ones. He will then discuss the issue of a possible complementarity between size and efficiency and show that even the smallest machines could be maximally efficient. He will also present a new point of view over what is work and what do thermal machines actually do. Finally, he will present a completely new approach to the foundations of thermodynamics that follows from these results.   Light refreshments will be served after the talk. The full schedule of lectures is as follows, see each separate entry in the online scientific calendar for more details: Lecture 1: Wednesday 25 January 2023 @16:00 hrs The smallest possible thermal machines and the foundations of thermodynamics  Lecture 2: Thursday 26 January 2023 @ 16:00 hrs Quantum non-locality and beyond Lecture 3: Friday 27 January 2023 @ 11:00 hrs Multiple-time states and the flow of time in quantum mechanics All are welcome to attend. The lectures will also be livestreamed from the ICTP website.