Scientific computing is a fundamentally interdisciplinary endeavour bridging applied mathematics, application disciplines such as various physical, life and social sciences, with software and computer engineering. Benefiting from tremendous advances in (super)computer hardware, scientific computation is now acknowledged as a third method of scientific discovery, complementary to experiment and theory. While scientific computing has recently lead to important advances in a number of fields, further progress is contingent on continued interaction and collaboration between different communities. Thus, the objective of this thematic program is to bring together prominent researchers (mathematicians as well as computational and application scientists) from across the globe who have contributed to the development of relevant computational methods and those who have pioneered their innovative use to address some of the fundamental problems in the following application domains:

• theoretical fluid mechanics
• quantum physics and chemistry
• multiscale physical phenomena

These themes are selected because they are at a point where scientific computation can finally provide answers to some of the long-standing open questions in both mathematical and the physical sciences (for which specific examples are given below). In addition, there are also numerous similarities, sometimes not initially evident, between the computational problems arising in these three fields which can be leveraged to foster cross-fertilization of ideas and approaches. In order to take advantage of these opportunities, it is necessary, now more than ever, to assemble a critical mass of researchers, and a thematic program at the Fields Institute is an ideal vehicle for such activities.