4,014 research outputs found
Balance between information gain and reversibility in weak measurement
We derive a tight bound between the quality of estimating a quantum state by
measurement and the success probability of undoing the measurement in arbitrary
dimensional systems, which completely describes the tradeoff relation between
the information gain and reversibility. In this formulation, it is clearly
shown that the information extracted from a weak measurement is erased through
the reversing process. Our result broadens the information-theoretic
perspective on quantum measurement as well as provides a standard tool to
characterize weak measurements and reversals.Comment: 5 pages, final versio
Near-Complete Teleportation of a Superposed Coherent State
The four Bell-type entangled coherent states, |\alpha>|-\alpha> \pm |-\alpha>
|\alpha> and |\alpha>|\alpha> \pm |-\alpha> |-\alpha>, can be discriminated
with a high probability using only linear optical means, as long as |\alpha| is
not too small. Based on this observation, we propose a simple scheme to almost
completely teleport a superposed coherent state. The nonunitary transformation,
that is required to complete the teleportation, can be achieved by embedding
the receiver's field state in a larger Hilbert space consisting of the field
and a single atom and performing a unitary transformation on this Hilbert
space.Comment: 4 pages,3 figures, Two columns, LaTex2
A generalized structure of Bell inequalities for bipartite arbitrary dimensional systems
We propose a generalized structure of Bell inequalities for arbitrary
d-dimensional bipartite systems, which includes the existing two types of Bell
inequalities introduced by Collins-Gisin-Linden-Massar-Popescu [Phys. Rev.
Lett. 88, 040404 (2002)] and Son-Lee-Kim [Phys. Rev. Lett. 96, 060406 (2006)].
We analyze Bell inequalities in terms of correlation functions and joint
probabilities, and show that the coefficients of correlation functions and
those of joint probabilities are in Fourier transform relations. We finally
show that the coefficients in the generalized structure determine the
characteristics of quantum violation and tightness.Comment: 6 pages, 1 figur
Concomitant Laparoendoscopic Single-Site Surgery for Ureterolithotomy and Contralateral Renal Cyst Marsupialization
A 63-year-old woman presented with acute right-flank pain and left-flank pain. Computed tomography identified a right ureter stone and a left renal cyst. The patient underwent concomitant laparoendoscopic single-site surgery (LESS) for ureterolithotomy and renal cyst marsupialization with the use of an Alexis® wound retractor, which was inserted through the umbilical incision. Flexible laparoscopic instruments and conventional rigid instruments were used during LESS following a procedure similar to that used with conventional laparoscopic surgery without additional transcutaneous ports. LESS may be more efficient at treating bilateral diseases than is conventional laparoscopic surgery
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