title: Fundamental quantum limit to the multiphoton absorption rate for monochromatic light.
abstract: The local multiphoton absorption rate for an arbitrary quantum state of monochromatic light, taking into account the photon number, momentum, and polarization degrees of freedom, is shown to have an upper bound that can be reached by coherent fields. This surprising result rules out any quantum enhancement of the multiphoton absorption rate by momentum entanglement.
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. mankei@mit.edu
authors.forename: Mankei
authors.initials: M
authors.lastname: Tsang