Iwata, Natsumi Retraction: Higher-Order Nonlocal Effects of a Relativistic Ponderomotive Force in High-Intensity Laser Fields [Phys. Rev. Lett. 112, 035002 (2014)]. [electronic resource] - Physical review letters Dec 2015 - 269902 p. digital Publication Type: Retraction Notice ISSN: 1079-7114 Standard No.: 10.1103/PhysRevLett.115.269902 doi