4 research outputs found
Free-electron interactions with photonic GKP states: universal control and quantum error correction
We show that the coherent interaction between free electrons and photons can
be used for universal control of continuous-variable photonic quantum states in
the form of Gottesman-Kitaev-Preskill (GKP) qubits. Specifically, we find that
electron energy combs enable non-destructive measurements of the photonic state
and can induce arbitrary gates. Moreover, a single electron interacting with
multiple photonic modes can create highly entangled states such as
Greenberger-Horne-Zeilinger states and cluster states of GKPs
Coherently amplified ultrafast imaging in a free-electron interferometer
Accessing the low-energy non-equilibrium dynamics of materials with
simultaneous spatial and temporal resolutions has been a bold frontier of
electron microscopy in recent years. One of the main challenges is the ability
to retrieve extremely weak signals while simultaneously disentangling amplitude
and phase information. Here, we present an algorithm-based microscopy approach
that uses light-induced electron modulation to demonstrate the coherent
amplification effect in electron imaging of optical near-fields. We provide a
simultaneous time-, space-, and phase-resolved measurement in a micro-drum made
from a hexagonal boron nitride membrane, visualizing the sub-cycle
spatio-temporal dynamics of 2D polariton wavepackets therein. The
phase-resolved measurement reveals vortex-anti-vortex singularities on the
polariton wavefronts, together with an intriguing phenomenon of a traveling
wave mimicking the amplitude profile of a standing wave. Our experiments show a
20-fold coherent amplification of the near-field signal compared to
conventional electron near-field imaging, resolving peak field intensities of
~W/cm2 (field amplitude of few kV/m). As a result, our work opens a path toward
spatio-temporal electron microscopy of biological specimens and quantum
materials - exciting yet sensitive samples, which are currently difficult to
investigate