1. Departament d'Economia i Empresa and Barcelona Graduate School of Economics, Universitat Pompeu Fabra, c/Ramon Trias Fargas, 25–27, 08005 Barcelona, Spain
2. Department of Physics, Center for Quantum Science and Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA
3. Division of Financial Engineering, School of Business, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA
4. Department of Mathematics, Baruch College, The City University of New York, 1 Bernard Baruch Way, New York, NY 10010, USA
5. Department of Mathematical Sciences, Ritsumeikan University, Noji-higashi 1-1-1, Kusatsu, Shiga 525-8577, Japan