We present the first observation of two-color free-electron laser (FEL) operation using a single electron beam, single optical cavity, and a stepped undulator. The undulator is divided into two sections, each having different deflection parameters, ${\mathit{K}}_{1}$ an...

Flaps can be detached from a thin film glued on a solid substrate by tearing and peeling. For flat substrates, it has been shown that these flaps spontaneously narrow and collapse in pointy triangular shapes. Here we show that various shapes, triangular, elliptic, acumi...

We introduce a new class of excitable systems with two-dimensional fast dynamics that includes inertia. A novel transition from excitability to relaxation oscillations is discovered where the usual Hopf bifurcation is followed by a cascade of period doubled and chaotic ...

We show that extensive statistical mechanics information can be obtained by the calculation of local densities such as local magnetizations and neighbor correlations, made possible by renormalization-group theory. This is illustrated with quenched random-bond, random-fi...

We evaluate the Onsager matrix for a system under time-periodic driving by considering all its Fourier components. By application of the second law, we prove that all the fluxes converge to zero in the limit of zero dissipation. Reversible efficiency can never be reache...

Water adsorption on polished (111) surfaces of ${\mathrm{BaF}}_{2}$ and ${\mathrm{CaF}}_{2}$ was studied at room temperature under ultrahigh vacuum conditions by optical second-harmonic generation. Above ${10}^{4}$ langmuirs, the total second-harmonic yield decreases wi...

We show that the existence of string order in a given quantum state is intimately related to the presence of a local symmetry by proving that both concepts are equivalent within the framework of finitely correlated states. Once this connection is established, we provide...

High-speed long-range quantum communication requires combining frequency multiplexed photonic channels with quantum memories. We experimentally demonstrate an integrated quantum frequency conversion protocol that can convert between wavelength division multiplexing chan...

On the basis of gauge invariance, it is proven in an elementary and straightforward manner, but without invoking any {\it ad hoc} assumption, that the existence of off-diagonal long-range order in one-particle reduced density matrix in Bose liquids implies both the irro...

We discuss the problem of a spin 1/2 impurity immersed in a spin S magnetically ordered background. We show that the problem maps onto a generalization of the dissipative two level system (DTLS) with two independent heat baths, associated with the Goldstone modes of the...