Erratum to: “Weak corrections to gluon-induced top–antitop hadro-production” [Phys. Lett. B 639 (2006) 513]

This is an Erratum to a Letter of ours [S. Moretti, M.R. Nolten, D.A. Ross, Phys. Lett. B 639 (2006) 513]. After its publication, we have discovered a mistake in a numerical program that affects the results presented therein. We provide here the corrected version.     

Comment on: “Quantum exam” [Phys. Lett. A 350 (2006) 174]

In the Letter [B.A. Nguyen, Phys. Lett. A 350 (2006) 174], a quantum exam protocol was presented. Here we show a cheating protocol, by which any student can get the other students' solution without being detected. Then we propose a possible modified protocol against this attacking strategy.     

Erratum to “Superradiant instability for black holes immersed in a magnetic field” [Phys. Lett. B 666 (2008) 283]

This is the erratum to the Letter [R.A. Konoplya, Phys. Lett. B 666 (2008) 283]. The formulas (18)–(20) are corrected, though the conclusions of the work have not changed.     

Erratum to: “Controlling complex dynamical networks with coupling delays to a desired orbit” [Phys. Lett. A 359 (2006) 42]

In this Letter, we indicate that the proposed sufficient condition in Letter [Z. Li, G. Feng, D., Hill, Phys. Lett. A 359 (2006) 42] does not hold, which cannot guarantee that the states of complex network with coupling delays globally exponentially synchronize with a desired orbit and it only applies to globally asymptotical synchronization with a desired orbit. For correcting the mistakes, a correct version of globally exponential synchronization is given and proved in this Letter.