Shaping an itinerant quantum field into a multimode squeezed vacuum by dissipation

We show that inducing sidebands in the emission of a single emitter into a one-dimensional waveguide, together with a dissipative repumping process, a photon ?eld is cooled down to a multimode squeezed vacuum. Our method does not require being in the strong coupling regime, works with a continuum of propagating ?eld modes, and leads to sources of tunable multimode squeezed light in circuit-QED systems.