9,305 research outputs found
On the Phase Transition of Corrupted Sensing
In \cite{FOY2014}, a sharp phase transition has been numerically observed
when a constrained convex procedure is used to solve the corrupted sensing
problem. In this paper, we present a theoretical analysis for this phenomenon.
Specifically, we establish the threshold below which this convex procedure
fails to recover signal and corruption with high probability. Together with the
work in \cite{FOY2014}, we prove that a sharp phase transition occurs around
the sum of the squares of spherical Gaussian widths of two tangent cones.
Numerical experiments are provided to demonstrate the correctness and sharpness
of our results.Comment: To appear in Proceedings of IEEE International Symposium on
Information Theory 201
Banking reforms, performance and risk in China
We investigate the impact of the banking reform started from 2005 on ownership structures in China on commercial banks’ profitability, efficiency and risk over the period 2000–2012, providing comprehensive evidence on the impact of banking reform in China. We find that banks on average tend to have higher profitability, lower risk and lower efficiency after the reforms, and the results are robust with our difference-in-difference approach. Our results also show that the Big 5 state-owned banks (SOCB) underperform banks with other types of ownership when risk is measured by non-performing loans (NPLs) over the entire study period but tend to have fewer NPLs than other banks during the post-reform period. Our results provide some supporting evidence on the ongoing banking reforms in China, suggesting that attracting strategic foreign investors and listing SOCBs on stock exchanges appear to be effective ways to help SOCBs deal with the problem of NPLs and manage their risk
Nonadiabatic noncyclic geometric quantum computation in Rydberg atoms
Nonadiabatic geometric quantum computation (NGQC) has been developed to
realize fast and robust geometric gate. However, the conventional NGQC is that
all of the gates are performed with exactly the sameamount of time, whether the
geometric rotation angle is large or small, due to the limitation of cyclic
condition. Here, we propose an unconventional scheme, called nonadiabatic
noncyclic geometric quantum computation(NNGQC), that arbitrary single- and
two-qubit geometric gate can be constructed via noncyclic non-Abeliangeometric
phase. Consequently, this scheme makes it possible to accelerate the
implemented geometric gatesagainst the effects from the environmental
decoherence. Furthermore, this extensible scheme can be applied invarious
quantum platforms, such as superconducting qubit and Rydberg atoms.
Specifically, for single-qubit gate,we make simulations with practical
parameters in neutral atom system to show the robustness of NNGQC and also
compare with NGQC using the recent experimental parameters to show that the
NNGQC can significantly suppress the decoherence error. In addition, we also
demonstrate that nontrivial two-qubit geometric gate can berealized via
unconventional Rydberg blockade regime within current experimental
technologies. Therefore, ourscheme provides a promising way for fast and robust
neutral-atom-based quantum computation.Comment: 6 pages, 6 figures. Published visio
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