10,121 research outputs found
Equidistribution from Fractals
We give a fractal-geometric condition for a measure on [0,1] to be supported
on points x that are normal in base n, i.e. such that the sequence x,nx,n^2
x,... equidistributes modulo 1. This condition is robust under C^1 coordinate
changes, and it applies also when n is a Pisot number and equidistribution is
understood with respect to the beta-map and Parry measure. As applications we
obtain new results (and strengthen old ones) about the prevalence of normal
numbers in fractal sets, and new results on measure rigidity, specifically
completing Host's theorem to multiplicatively independent integers and proving
a Rudolph-Johnson-type theorem for certain pairs of beta transformations.Comment: 46 pages. v3: minor corrections and elaboration
An Exchange Mechanism to Coordinate Flexibility in Residential Energy Cooperatives
Energy cooperatives (ECs) such as residential and industrial microgrids have
the potential to mitigate increasing fluctuations in renewable electricity
generation, but only if their joint response is coordinated. However, the
coordination and control of independently operated flexible resources (e.g.,
storage, demand response) imposes critical challenges arising from the
heterogeneity of the resources, conflict of interests, and impact on the grid.
Correspondingly, overcoming these challenges with a general and fair yet
efficient exchange mechanism that coordinates these distributed resources will
accommodate renewable fluctuations on a local level, thereby supporting the
energy transition. In this paper, we introduce such an exchange mechanism. It
incorporates a payment structure that encourages prosumers to participate in
the exchange by increasing their utility above baseline alternatives. The
allocation from the proposed mechanism increases the system efficiency
(utilitarian social welfare) and distributes profits more fairly (measured by
Nash social welfare) than individual flexibility activation. A case study
analyzing the mechanism performance and resulting payments in numerical
experiments over real demand and generation profiles of the Pecan Street
dataset elucidates the efficacy to promote cooperation between co-located
flexibilities in residential cooperatives through local exchange.Comment: Accepted in IEEE ICIT 201
A spintronic source of circularly polarized single photons
We present a spintronic single photon source which emits circularly polarized
light, where the helicity is determined by an applied magnetic field. Photons
are emitted from an InGaAs quantum dot inside an electrically operated spin
light-emitting diode, which comprises the diluted magnetic semiconductor
ZnMnSe. The circular polarization degree of the emitted light is high, reaching
83% at an applied magnetic field of 2T and 96% at 6 T. Autocorrelation traces
recorded in pulsed operation mode prove the emitted light to be antibunched.
The two circular polarization states could be used for representing quantum
states |0> and |1> in quantum cryptography implementations
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