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An atom moving in vacuum at constant velocity parallel to a surface experiences a frictional force induced by the dissipative interaction with quantum electromagnetic fluctuations. We show that the combination of nonequilibrium dynamics, anomalous Doppler effect and spin-momentum locking of light mediates an intriguing interplay between the atom's translational and rotational motion. This behavior deeply affects the drag force in a way that is reminiscent of classical rolling friction. Our fully non-Markovian and nonequilibrium description reveals counterintuitive features characterizing the atom's velocity-dependent rotational dynamics. These results prompt interesting directions for tuning the interaction and for investigating nonequilibrium dynamics as well as the properties of confined light.Quantum light-matter interactions continue to fascinate with intriguing and non-intuitive phenomena. During the last years, many interesting results involving nonequilibrium physics and light confinement in photonic and plasmonic systems have been reported. Although systems out of equilibrium are very common in nature, only recently have intense investigations unraveled their relevance for both fundamental and applied research [1,2]. On the other hand, despite light confinement is already known for inducing many fascinating effects, it still continues to surprise and is currently attracting attention for conveying spin-orbit interactions of light [3][4][5]. Here, we combine these fields of research within a larger framework: We show that, when an atom is forced to move parallel to a surface, a quantum rolling frictional dynamics results from the nonequilibrium interplay of the atomic translational and rotational motion. Despite the underlying physics resembles somewhat that of a body rolling on a surface, it features many interesting counterintuitive aspects.Due to vacuum fluctuations, light-matter interactions lead to the occurrence of non-conservative (frictional) forces on electrically neutral and non-magnetic objects [6,7]. These forces are quantum in nature and the physics behind quantum friction is related to the quantum Cherenkov effect through the anomalous-Doppler effect [8][9][10][11]. In this process, real photons are extracted from vacuum at the cost of the object's kinetic energy; they are absorbed and re-emitted producing a fluctuating momentum recoil [12]. When only the atomic translational motion is considered, spin-zero photons are absorbed and re-emitted, and a net quantum frictional force that opposes the translational motion appears. This anisotropic process was investigated in many scenarios during the last decade [6,[13][14][15][16][17][18][19][20] and its connection to nonequilibrium physics was recently highlighted [21]. In this Letter we show that, when the rotational degrees of freedom are involved in the dynamics, the atom can also exchange angular momentum, absorbing and emitting photons with nonzero spin. However, due to nonequilibrium physics, the anomalous-Doppler effect and the spinmomentum...

We investigate the influence of spatial dispersion on atom-surface quantum friction. We show that for atom-surface separations shorter than the carrier's mean free path within the material, the frictional force can be several orders of magnitude larger than that predicted by local optics. In addition, when taking into account spatial dispersion effects, we show that the commonly used local thermal equilibrium approximation underestimates by approximately 95% the drag force, obtained by employing the recently reported nonequilibrium fluctuation-dissipation relation for quantum friction. Unlike the treatment based on local optics, spatial dispersion in conjunction with corrections to local thermal equilibrium not only change the magnitude but also the distance scaling of quantum friction.

The quantum thermodynamical properties of (quasi-normal) overdamped electromagnetic modes (eddy currents) are investigated in the context of the magnetic Casimir-Polder interaction. The role of the material response in terms of spatially local and nonlocal material models is discussed. In particular, the focus is set on the system's entropy in the limit of low temperatures. In specific circumstances the spatially local (Drude) model reveals an "entropy defect", while spatial dispersion leads to a more regular behavior. We present a detailed description of this phenomenon and of the different mechanisms at work in the system with regard to the eddy modes' properties. Extensively discussing classical and quantum features, we relate our results to the wide range of literature and draw intriguing connections to seemingly distant fields as, e.g., the theory of magnetohydrodynamics and superconductivity.

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