Deterministically encoding quantum information using 100-photon Schrödinger cat states.
In contrast to a single quantum bit, an oscillator can store multiple excitations and coherences provided one has the ability to generate and manipulate complex multiphoton states. We demonstrate multiphoton control by using a superconducting transmon qubit coupled to a waveguide cavity resonator with a highly ideal off-resonant coupling. This dispersive interaction is much greater than decoherence rates and higher-order nonlinearities to allow simultaneous manipulation of hundreds of photons. With a tool set of conditional qubit-photon logic, we mapped an arbitrary qubit state to a superposition of coherent states, known as a "cat state." We created cat states as large as 111 photons and extended this protocol to create superpositions of up to four coherent states. This control creates a powerful interface between discrete and continuous variable quantum computation and could enable applications in metrology and quantum information processing.
Department of Physics and Department of Applied Physics, Yale University, New Haven, CT 06511, USA.
Brian
B
Vlastakis
Gerhard
G
Kirchmair
Zaki
Z
Leghtas
Simon E
SE
Nigg
Luigi
L
Frunzio
S M
SM
Girvin
Mazyar
M
Mirrahimi
M H
MH
Devoret
R J
RJ
Schoelkopf