The conditional mutual information (CMI) ?(A:C|B) quantifies the amount of correlations shared between A and C given B. It therefore functions as a more general quantifier of bipartite correlations in multipartite scenarios, playing an important role in the theory of quantum Markov chains. In this paper we carry out a detailed study on the behavior of the CMI in non-equilibrium steady-states (NESS) of a quantum chain placed between two baths at different temperatures. These results are used to shed light on the mechanisms behind ballistic and diffusive transport regimes and how they affect correlations between different parts of a chain. We carry our study for the specific case of a 1D bosonic chain subject to local Lindblad dissipators at the boundaries. In addition, the chain is also subject to self-consistent reservoirs at each site, which are used to tune the transport between ballistic and diffusive. As a result, we find that the CMI is independent of the chain size L in the ba...

We propose and analyze a mechanism for rectification of spin transport through a small junction between two spin baths or leads. For interacting baths, we show that transport is conditioned on the spacial asymmetry of the quantum junction mediating the transport, and attribute this behavior to a gapped spectral structure of the lead-system-lead configuration. For noninteracting leads, a minimal quantum model that allows for spin rectification requires an interface of only two interacting two-level systems. In our paper, we have performed a thorough study of the current, including its time dependence and steady-state value. We obtain approximate results with a weak-coupling Born master equation in excellent agreement with matrix-product-state calculations that are extrapolated in time by mimicking absorbing boundary conditions. These results should be observable in controlled spin systems realized with cold atoms, trapped ions, or in electrons in quantum dot arrays.

Exploiting the relative entropy of coherence, we isolate the coherent contribution in the energetics of a driven nonequilibrium quantum system. We prove that a division of the irreversible work can be made into a coherent and incoherent part. This provides an operational criterion for quantifying the coherent contribution in a generic nonequilibrium transformation on a closed quantum system. We then study such a contribution in two physical models of a driven qubit and kicked rotor. In addition, we also show that coherence generation is connected to the nonadiabaticity of a processes, for which it gives the dominant contribution for slow-enough transformations. The amount of generated coherence in the energy eigenbasis is equivalent to the change in diagonal entropy, and here we show that it fulfills a fluctuation theorem.

We present an analysis of Planck satellite data on the Coma cluster observed via the Sunyaev-Zeldovich effect. Thanks to its great sensitivity, Planck is able, for the first time, to detect SZ emission up to r ≈ 3 × R500. We test previously proposed spherically symmetric models for the pressure distribution in clusters against the azimuthally averaged data. In particular, we find that the Arnaud et al. (2010, A&A, 517, A92) “universal” pressure profile does not fit Coma, and that their pressure profile for merging systems provides a reasonable fit to the data only at r < R500; by r = 2 × R500 it underestimates the observed y profile by a factor of ≃2. This may indicate that at these larger radii either: i) the cluster SZ emission is contaminated by unresolved SZ sources along the line of sight; or ii) the pressure profile of Coma is higher at r > R500 than the mean pressure profile predicted by the simulations used to constrain the models. The Planck image shows significan...

We have developed an approximate technique, based on the principles of multi-mode Gaussian optics, for studying the behaviour of shaped off-axis mirrors. We describe a mirror as an inclined phase-transforming plane, where the phase transformation across the plane is determined by the depth of the mirror as a function of position. The scattering matrix is calculated in the usual way by evaluating the overlap integrals over some surface for which the amplitudes and phases of the incoming and outgoing fields are known; because, however, the modes are not orthogonal over the surface of interest, a system of linear equations has to be solved. We demonstrate the “thin-mirror” technique by studying the behaviour of paraboloidal and ellipsoidal mirros, and we show how the performance of measured and approximate surfaces can be assessed.

We consider a Whitham equation as an alternative for the Korteweg–de Vries (KdV) equation in which the third derivative is replaced by the integral of a kernel, i.e., ηxxx in the KdV equation is replaced by ∫∞−∞Kν(x−ξ)ηξ(ξ,t)dξ. The kernel Kν(x) satisfies the conditions limν→∞Kν(x) = δ″(x), where δ(x) is the Dirac delta function and limν→0Kν(x) = 0. The questions studied here, by means of numerical examples, are whether adjustment of the parameter ν produces both continuous solutions and shocks of the kernel equation and how well they represent KdV solutions and solutions of the underlying hyperbolic system. A typical example is for resonant forced oscillations in a closed shallow water tank governed by the kernel equation, which are compared with those governed by a partial differential equation. The continuous solutions of the kernel equation associated with frequency dispersion in the KdV equations limit to the shocks of the shallow water equations as ν → 0. Two experimental prob...

The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra CℓEE and CℓBB over the multipole range 40 <ℓ< 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, Cℓ ∝ ℓα, with exponents αEE,BB = −2.42 ± 0.02. The amplitudes of the polarization...

Kondati Natarajan, Suresh; Nolan, Michael; Theofanis, Patrick; Mokhtarzadeh, Charles; Clendenning, Scott B.

Abstract:

Thermal atomic layer etch (ALE), facilitating the removal of up to one monolayer of material per cycle, is growing in importance for thin-film processing. The number of available ALE processes is much smaller than for atomic layer deposition, its complementary growth process. Quantum chemical simulations are a key approach in the development of new thermal ALE processes, however, methodologies and workflows need to be developed. In this regard, the present paper reports a simulation-based approach toward the development of new thermal ALE processes using metallic cobalt as a test case. We demonstrate a predictive process discovery approach for ALE in which target volatile etch products and the corresponding gas phase reactants are chosen from the literature, an overall ALE cycle for each combination of reactant is investigated for thermochemical favorability, and the detailed mechanisms of the individual reaction steps in the proposed ALE processes are studied using density function...