  Quantum physics allows for entanglement between microscopic and macroscopic
objects, described by discrete and continuous variables, respectively. As in
Schr\"odinger's famous cat gedanken experiment, a box enclosing the objects can
keep the entanglement alive. For applications in quantum information
processing, however, it is essential to access the objects and manipulate them
with suitable quantum tools. Here we reach this goal and deterministically
generate entangled light-matter states by reflecting a coherent light pulse
with up to four photons on average from an optical cavity containing one atom.
The quantum light propagates freely and reaches a remote receiver for quantum
state tomography. We produce a plethora of quantum states and observe
negative-valued Wigner functions, a characteristic sign of non-classicality. As
a first application, we demonstrate a quantum-logic gate between an atom and a
light pulse, with the photonic qubit encoded in the phase of the light field.
