1,979 research outputs found
Dequantization via quantum channels
For a unital completely positive map ("quantum channel") governing the
time propagation of a quantum system, the Stinespring representation gives an
enlarged system evolving unitarily. We argue that the Stinespring
representations of each power of the single map together encode the
structure of the original quantum channel and provides an interaction-dependent
model for the bath. The same bath model gives a "classical limit" at infinite
time in the form of a noncommutative "manifold" determined by the
channel. In this way a simplified analysis of the system can be performed by
making the large- approximation. These constructions are based on a
noncommutative generalization of Berezin quantization. The latter is shown to
involve very fundamental aspects of quantum-information theory, which are
thereby put in a completely new light
Revisiting the Merit-Order Effect of Renewable Energy Sources
An on-going debate in the energy economics and power market community has
raised the question if energy-only power markets are increasingly failing due
to growing feed-in shares from subsidized renewable energy sources (RES). The
short answer to this is: No, they are not failing. Energy-based power markets
are, however, facing several market distortions, namely from the gap between
the electricity volume traded at day-ahead markets versus the overall
electricity consumption as well as the (wrong) regulatory assumption that
variable RES generation, i.e., wind and photovoltaic (PV), truly have zero
marginal operation costs. In this paper we show that both effects over-amplify
the well-known merit-order effect of RES power feed-in beyond a level that is
explainable by underlying physical realities, i.e., thermal power plants being
willing to accept negative electricity prices to be able to stay online due to
considerations of wear & tear and start-stop constraints. We analyze the
impacts of wind and PV power feed-in on the day-ahead market for a region that
is already today experiencing significant feed-in tariff (FIT)-subsidized RES
power feed-in, the EPEX German-Austrian market zone (20% FIT share).
Our analysis shows that, if the necessary regulatory adaptations are taken,
i.e., increasing the day-ahead market's share of overall load demand and using
the true marginal costs of RES units in the merit-order, energy-based power
markets can remain functional despite high RES power feed-in.Comment: Working Paper (9 pages, 11 figures, 5 tables) - Some revisions since
last version (10 February 2014). (Under 2nd review for IEEE Transactions on
Power Systems
- …