9,490 research outputs found
Empirical Patterns in Google Scholar Citation Counts
Scholarly impact may be metricized using an author's total number of
citations as a stand-in for real worth, but this measure varies in
applicability between disciplines. The detail of the number of citations per
publication is nowadays mapped in much more detail on the Web, exposing certain
empirical patterns. This paper explores those patterns, using the citation data
from Google Scholar for a number of authors.Comment: 6 pages, 8 figures, submitted to Cyberpatterns 201
Sampling arbitrary photon-added or photon-subtracted squeezed states is in the same complexity class as boson sampling
Boson sampling is a simple model for non-universal linear optics quantum
computing using far fewer physical resources than universal schemes. An input
state comprising vacuum and single photon states is fed through a Haar-random
linear optics network and sampled at the output using coincidence
photodetection. This problem is strongly believed to be classically hard to
simulate. We show that an analogous procedure implements the same problem,
using photon-added or -subtracted squeezed vacuum states (with arbitrary
squeezing), where sampling at the output is performed via parity measurements.
The equivalence is exact and independent of the squeezing parameter, and hence
provides an entire class of new quantum states of light in the same complexity
class as boson sampling.Comment: 5 pages, 2 figure
Boson sampling with displaced single-photon Fock states versus single-photon-added coherent states---The quantum-classical divide and computational-complexity transitions in linear optics
Boson sampling is a specific quantum computation, which is likely hard to
implement efficiently on a classical computer. The task is to sample the output
photon number distribution of a linear optical interferometric network, which
is fed with single-photon Fock state inputs. A question that has been asked is
if the sampling problems associated with any other input quantum states of
light (other than the Fock states) to a linear optical network and suitable
output detection strategies are also of similar computational complexity as
boson sampling. We consider the states that differ from the Fock states by a
displacement operation, namely the displaced Fock states and the photon-added
coherent states. It is easy to show that the sampling problem associated with
displaced single-photon Fock states and a displaced photon number detection
scheme is in the same complexity class as boson sampling for all values of
displacement. On the other hand, we show that the sampling problem associated
with single-photon-added coherent states and the same displaced photon number
detection scheme demonstrates a computational complexity transition. It
transitions from being just as hard as boson sampling when the input coherent
amplitudes are sufficiently small, to a classically simulatable problem in the
limit of large coherent amplitudes.Comment: 7 pages, 3 figures; published versio
Scalable boson-sampling with time-bin encoding using a loop-based architecture
We present an architecture for arbitrarily scalable boson-sampling using two
nested fiber loops. The architecture has fixed experimental complexity,
irrespective of the size of the desired interferometer, whose scale is limited
only by fiber and switch loss rates. The architecture employs time-bin
encoding, whereby the incident photons form a pulse train, which enters the
loops. Dynamically controlled loop coupling ratios allow the construction of
the arbitrary linear optics interferometers required for boson-sampling. The
architecture employs only a single point of interference and may thus be easier
to stabilize than other approaches. The scheme has polynomial complexity and
could be realized using demonstrated present-day technologies.Comment: 7 pages, 7 figure
Foreign Bond Markets and Financial Market Development: International Perspectives
The domestic bond markets of the Asia and Pacific region have grown considerably since the Asian financial crisis of 1997, although they remain undeveloped relative to the region's weight in the world economy. This paper proposes that in order to encourage further development of these markets, regulators should make them more accessible to foreign borrowers. To that end we offer insights into the nature and mechanics of foreign bond issuance by investigating the key characteristics of 3,132 foreign bonds issued in 14 countries (other than the United States) between July 1928 and June 2009. We found that the foreign borrowers that tap domestic markets are overwhelmingly of high credit quality and comprise sovereigns, supranationals, and major financial institutions. There is a preference for simple fixed-rate payment structures, which can then be swapped into the currency and coupon type of choice using currency and interest rate derivatives. On the whole, the long-term viability of foreign bond markets appears linked to the presence of highly liquid foreign exchange and derivatives markets that facilitate risk management and transformation, enabling regulation that facilitates cooperation with market participants, the presence of benchmark issues, and competitive pricing between alternate market segments.bond markets; financial market development; foreign bonds
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