11 research outputs found
Correlation and dimensional effects of trions in carbon nanotubes
We study the binding energies of singlet trions, i.e. charged excitons, in
carbon nanotubes. The problem is modeled, through the effective-mass model, as
a three-particle complex on the surface of a cylinder, which we investigate
using both one- and two-dimensional expansions of the wave function. The
effects of dimensionality and correlation are studied in detail. We find that
the Hartree-Fock approximation significantly underestimates the trion binding
energy. Combined with band structures calculated using a non-orthogonal nearest
neighbour tight binding model, the results from the cylinder model are used to
compute physical binding energies for a wide selection of carbon nanotubes. In
addition, the dependence on dielectric screening is examined. Our findings
indicate that trions are detectable at room temperature in carbon nanotubes
with radius below 8{\AA}
Towards Hybrid Classical-Quantum Computation Structures in Wirelessly-Networked Systems
With unprecedented increases in traffic load in today's wireless networks,
design challenges shift from the wireless network itself to the computational
support behind the wireless network. In this vein, there is new interest in
quantum-compute approaches because of their potential to substantially speed up
processing, and so improve network throughput. However, quantum hardware that
actually exists today is much more susceptible to computational errors than
silicon-based hardware, due to the physical phenomena of decoherence and noise.
This paper explores the boundary between the two types of
computation---classical-quantum hybrid processing for optimization problems in
wireless systems---envisioning how wireless can simultaneously leverage the
benefit of both approaches. We explore the feasibility of a hybrid system with
a real hardware prototype using one of the most advanced experimentally
available techniques today, reverse quantum annealing. Preliminary results on a
low-latency, large MIMO system envisioned in the 5G New Radio roadmap are
encouraging, showing approximately 2--10X better performance in terms of
processing time than prior published results.Comment: HotNets 2020: Nineteenth ACM Workshop on Hot Topics in Networks
(https://doi.org/10.1145/3422604.3425924