arXiv:1102.4691 · Physical Review A
Possible use of a Cooper-pair box for low-dose electron microscopy
Hiroshi Okamoto
Abstract
A transmission electron microscope that takes advantage of superconducting quantum circuitry is proposed. The microscope is designed to improve the image contrast of radiation-sensitive weak-phase objects, in particular, biological specimens. The objective in this setting is to measure the phase shift of the probe electron wave to a precision \ensuremath{\Delta}\ensuremath{\theta} within the number of electrons $N$ that does not destroy the specimen. In conventional electron microscopy \ensuremath{\Delta}\ensuremath{\theta} scales as \ensuremath{\sim}1/${N}^{1/2}$, which falls short of the Heisenberg limit \ensuremath{\sim}1/$N$. To approach the latter by using quantum entanglement, we propose a design that involves a Cooper-pair box placed on the surface of an electrostatic electron mirror in the microscope. Significant improvement could be attained if inelastic scattering processes are sufficiently delocalized.