Even if non-adiabatic perturbations are generated in multi-field inflation, the perturbations will become adiabatic if the universe after inflation enters an era of local thermal equilibrium, with no non-zero conserved quantities, and will remain adiabatic as long as the wavelength is outside the horizon, even when local thermal equilibrium no longer applies. Small initial non-adiabatic perturb...

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Self-consistent particle-in-cell simulations are performed to verify earlier theoretical predictions of adiabatic thermal beams in a periodic solenoidal magnetic focusing field [K. In particular, results are obtained for adiabatic thermal beams that do not rotate in the Larmor ...

We present a gauge-invariant formalism to study the evolution of curvature perturbations in a Friedmann-Robertson-Walker universe filled by multiple interacting fluids. We resolve arbitrary perturbations into adiabatic and entropy components and derive their coupled evolution equations. We demonstrate that perturbations obeying a generalised adiabatic condition remain adiabatic in the large-sca...

We present a general formalism for describing stimulated Raman adiabatic passage in a multilevel atom. The atom is assumed to have two ground state manifolds a and b and an excited state manifold e, and the adiabatic passage is carried out by resonantly driving the a-e and b-e transitions with time-dependent fields. Our formalism gives a complete description of the adiabatic passage process and...

We present a geometrical representation of the process of sum frequency generation in the undepleted pump approximation, in analogy with the known optical Bloch equations. We use this analogy to propose a technique for achieving both high efficiency and large bandwidth in sum frequency conversion using the adiabatic inversion scheme. The process is analogous with rapid adiabatic passage in NMR,...

Expressions for a K-adiabatic master equation for a bimolecular recombination rate constant krec are derived for a bimolecular reaction forming a complex with a single well or complexes with multiple well, where K is the component of the total angular momentum along the axis of least moment of inertia of the recombination product. The K-active master equation is also considered. The exact analy...

We have studied survival and rotational excitation probabilities of H(2)(v(i) = 1, J(i) = 1) and D(2)(v(i) = 1, J(i) = 2) upon scattering from Cu(111) using six-dimensional (6D) adiabatic (quantum and quasi-classical) and non-adiabatic (quasi-classical) dynamics. Non-adiabatic dynamics, based on a friction model, has been used to analyze the role of electron-hole pair excitations. Comparison be...

Chemical reactions that occur in the ground electronic state are described well by invoking the Born-Oppenheimer approximation, which allows their development to be rationalized by nuclear rearrangements that smoothly traverse an adiabatic potential energy surface. The situation is different, however, for reactions in electronically excited states, where non-adiabatic transitions occur between ...

Adiabatic logic style is Proving to be an attractive solution for low power digital design. The paper investigates low – power characteristics of complementary pass -transistor logic (CPL) circuits using AC power supply. The two-phase power-clock scheme is more suitable for the design of flip-flops and sequential circuits because it uses fewer transistors. The Adiabatic flip-flop have large ene...