Comment on: “Exposed-key weakness of αη” [Phys. Lett. A 370 (2007) 131]

We show that the insecurity claim of the αη cryptosystem made by C. Ahn and K. Birnbaum in [C. Ahn, K. Birnbaum, Phys. Lett. A 370 (2007) 131] under heterodyne attack is based on invalid extrapolations of Shannon's random cipher analysis and on an invalid statistical independence assumption. We show, both for standard ciphers and αη, that expressions of the kind given by Ahn and Birnbaum can at best be interpreted as security lower bounds.     

Reply to: “Comment on: ‘Spherical Kadomtsev–Petviashvili equation and nebulons for dust ion-acoustic waves with symbolic computation’ ” [Phys. Lett. A 361 (2007) 520]

Dusty plasmas exist almost everywhere in the Universe and relevant nonlinear studies are encouragingly going to non-planar geometry. On our recent construction of a spherical Kadomtsev–Petviashvili model for the dust-ion-acoustic waves in a cosmic dusty plasma [B. Tian, Y.-T. Gao, Phys. Lett. A 340 (2005) 243], Hong [W.P. Hong, Phys. Lett. A (2006), doi:10.1016/j.physleta.2006.11.021, in press] comments that certain interesting coordinate transformations exist, with presentation of a transformed equation (TE) and nebulon solutions. In this Reply, we point out that the TE is valuable to the studies on both cosmic plasmas and applied mathematics. We obtain an auto-Bäcklund transformation on the TE and more general nebulons. With series of pictures, we discuss nebulon structures out of the TE, and address that there are cosmic plasma systems for which the TE is valid. We remove a constraint set in that Comment so that the TE can be useful for the Saturn-F-ring-typed dusty plasmas as well.     

Reply to “Comment on: ‘Multi-photon Rabi model: Generalized parity and its applications’ [Phys. Lett. A 377 (2013) 3205]” [Phys. Lett. A 378 (2014) 1969]

We show that the claims stated in the comment made by Chi-Fai Lo on our paper [Phys. Lett. A 377 (2013) 3205] neither contradict nor falsify our results.     

Comment on: “Entanglement in three coupled oscillators” [Phys. Lett. A 384 (2020) 126134]

In this comment we analyze a method for the solution of the eigenvalue equation for three coupled harmonic oscillators proposed recently. We argue that the authors did not obtain the frequencies and coordinates of the normal modes that make the Hamiltonian operator diagonal but merely six transcendental equations for the relevant parameters that they did not attempt to solve. We derive the conditions for the existence of bound states that the authors did not appear to be able to obtain probably because of the complexity exhibited by those equations.     

Erratum to: “Quantum dissipative dynamics using the Doebner–Goldin equation” [Phys. Lett. A 376 (2012) 3033]

A few misprints appearing in the Letter [Phys. Lett. A 376 (2012) 3033] are corrected.     

Comment on: “Two elementary proofs of the Wigner theorem on symmetry in quantum mechanics” [Phys. Lett. A 372 (2008) 6847]

The second of the two proofs of the Wigner theorem on symmetry in quantum mechanics given in Simon et al. (2008) [1] is reexamined and refined to remove a possible gap in the argument presented there.     

Comment on ＂Application of the （G＇/G）-Expansion Method for Nonlinear Evolution Equations＂ [Phys. Lett. A 372 （2008）3400]

In this paper, some travelling wave solutions involving parameters of the Modified Zakharov-Kuznetsov equation [Phys. Lett. A 372 （2008） 3400] are investigated. We will show that these solutions are not new travelling wave solutions.     

Addendum to: “Geometrical and topological aspects of electrostatics on Riemannian manifolds” [J. Geom. Phys. 57 (8) (2007) 1679–1696]

In this note we discuss and solve several open problems posed in our recent paper “Geometrical and topological aspects of electrostatics on Riemannian manifolds”, also published in this journal. Some minor mistakes therein are corrected as well.     

Comment on “Convergence of macrostates under reproducible processes” [Phys. Lett. A 374 (2010) 3715]

In this Letter, two counterexamples show that the superadditivity inequality of relative entropy is not true even for the full-ranked quantum states. Thus, an inequality of quantum channels and complementary channels is not also true. Finally, a conjecture of weak superadditivity inequality is presented.     

Reply to the Comment by F. Kožíšek et al. on “Evidence for the existence of stable-water-clusters at room temperature and normal pressure” [Phys. Lett. A 373 (2009) 3872]

After discussing various points raised in a recent comment by F. Ko?íšek et al., who claim that our Letter “Evidence for the existence of stable-water-clusters at room temperature and normal pressure” (Phys. Lett. A 373 (2009) 3872) is unclear and the evidence is scant, we conclude that their arguments are wrong.     

Corrigendum to “Constraints on operator ordering from third quantization” [Ann. Phys. 365 (2016) 54–65]

In our previous paper Ohkuwa et al. (2016) corrigendum was found in Eqs. (3.4) and (3.6). However, conclusions of our previous paper are not changed.     

Addendum to: “Ricci-flat holonomy: A classification” [J. Geom. Phys. 57 (6) 1457–1475]: The case of spin(10)

This note fills a hole in the author’s previous paper “Ricci-flat holonomy: A classification”, by dealing with irreducible holonomy algebras that are subalgebras or real forms of C⊕spin(10,C)$\mathbb{C}\oplus \mathfrak{s}\mathfrak{p}\mathfrak{i}\mathfrak{n}(10,\mathbb{C})$. These all turn out to be of Ricci type.     

Comment on “Spherical particle Brownian motion in viscous medium as non-Markovian random process” [Phys. Lett. A 375 (2011) 4113]

In this comment, we show that the results presented in Letter “Spherical particle Brownian motion in viscous medium as non-Markovian random process” are not new, the old results from the literature are not correctly recalculated, and the used method of integral transforms is not applicable for consideration of the Brownian motion with memory.     

Comment on ‘Šilnikov-type orbits of Lorenz-family systems’ [Physica A 375 (2007) 438–446]

In the commented paper, the authors consider a four-parameter family of three-dimensional autonomous systems that includes the widely studied systems of Lorenz, Chen and Lü. Their goal is to rigorously prove the existence of Šilnikov chaos in this Lorenz-family via the Šilnikov criterion. They use an undetermined coefficient method to demonstrate the presence of heteroclinic orbits. In this comment we point out that their analysis is erroneous. The odd function they consider for the first component of the Šilnikov heteroclinic orbit cannot represent such global connection. Thus, the main result of their paper, Theorem 2, is incorrect.