39,177 research outputs found
Explaining the Policy Constraints of Anti-democratic Regimes by Means of Sequential OLS-Regressions
One of the key problems of many sociological regression models is their modest explanatory power. This has not only to do with the insufficient development of the underlying theories but also with the free will of the concerned social actors, which manifests itself in irrational, spontaneous, and sometimes even arbitrary decisions. The foreign and economic policy of the US government under Donald Trump is an excellent example of this source of indeterminacy.
An alternative and more promising approach is an explanation of the constraints of social behaviour by the unequal distribution of power resources and the competing interests of the actors concerned. This approach requires, on the one hand, enough observational data which include cases that reached the analysed constraints. On the other hand, there is a need for statistical procedures which estimate and explain these constraints. Assuming that sufficient amounts of data are available, this paper proposes the use of sequential OLS regressions, which eliminate step by step non-critical observations in order to identify the cases that reached the mentioned constraints.
For illustrative purposes, the author analyses the policy space of anti-democratic regimes with regard to their possibilities of curbing democracy. On the basis of the democracy scores of Freedom House, the author explores the governmental constraints set by (i) national civil societies and (ii) international NGOs for the promotion of political/civil rights. The related sequential regressions allow for an assessment of how effective the different constraints are and how far democracy may deteriorate in the worst case under given structural conditions
Correlating thermal machines and the second law at the nanoscale
Thermodynamics at the nanoscale is known to differ significantly from its
familiar macroscopic counterpart: the possibility of state transitions is not
determined by free energy alone, but by an infinite family of free-energy-like
quantities; strong fluctuations (possibly of quantum origin) allow to extract
less work reliably than what is expected from computing the free energy
difference. However, these known results rely crucially on the assumption that
the thermal machine is not only exactly preserved in every cycle, but also kept
uncorrelated from the quantum systems on which it acts. Here we lift this
restriction: we allow the machine to become correlated with the microscopic
systems on which it acts, while still exactly preserving its own state.
Surprisingly, we show that this restores the second law in its original form:
free energy alone determines the possible state transitions, and the
corresponding amount of work can be invested or extracted from single systems
exactly and without any fluctuations. At the same time, the work reservoir
remains uncorrelated from all other systems and parts of the machine. Thus,
microscopic machines can increase their efficiency via clever "correlation
engineering" in a perfectly cyclic manner, which is achieved by a catalytic
system that can sometimes be as small as a single qubit (though some setups
require very large catalysts). Our results also solve some open mathematical
problems on majorization which may lead to further applications in entanglement
theory.Comment: 11+13 pages, 5 figures. Added some clarifications and corrections;
results unchanged. Close to published versio
Spectroscopic parameters and rest frequencies of isotopic methylidynium, CH+
Astronomical observations toward Sagittarius B2(M) as well as other sources
with APEX have recently suggested that the rest frequency of the J = 1 - 0
transitions of 13CH+ is too low by about 80 MHz. Improved rest frequencies of
isotopologs of methylidynium should be derived to support analyses of spectral
recording obtained with the ongoing Herschel mission or the upcoming SOFIA.
Laboratory electronic spectra of four isotopologs of CH+ have been subjected to
one global least-squares fit. Laboratory data for the J = 1 - 0 ground state
rotational transitions of CH+, 13CH+, and CD+, which became available during
the refereeing process, have been included in the fit as well. An accurate set
of spectroscopic parameters has been obtained together with equilibrium bond
lengths and accurate rest frequencies for six CH+ isotopologs: CH+, 13CH+,
13CD+, CD+, 14CH+, and CT+. The present data will be useful for the analyses of
or SOFIA observations of methylidynium isotopic species.Comment: Astronomy and Astrophysics, accepted as Letter; 4 (here 5) page
Quantum Horn's lemma, finite heat baths, and the third law of thermodynamics
Interactions of quantum systems with their environment play a crucial role in
resource-theoretic approaches to thermodynamics in the microscopic regime.
Here, we analyze the possible state transitions in the presence of "small" heat
baths of bounded dimension and energy. We show that for operations on quantum
systems with fully degenerate Hamiltonian (noisy operations), all possible
state transitions can be realized exactly with a bath that is of the same size
as the system or smaller, which proves a quantum version of Horn's lemma as
conjectured by Bengtsson and Zyczkowski. On the other hand, if the system's
Hamiltonian is not fully degenerate (thermal operations), we show that some
possible transitions can only be performed with a heat bath that is unbounded
in size and energy, which is an instance of the third law of thermodynamics. In
both cases, we prove that quantum operations yield an advantage over classical
ones for any given finite heat bath, by allowing a larger and more physically
realistic set of state transitions.Comment: 15+4 pages, 6 figures. Version accepted for publication in Quantu
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