Quantum authentication of classical messages

Although key distribution is arguably the most studied context on which to apply quantum cryptographic techniques, message authentication, i.e., certifying the identity of the message originator and the integrity of the message sent, can also benefit from the use of quantum resources. Classically, message authentication can be performed by techniques based on hash functions. However, the security of the resulting protocols depends on the selection of appropriate hash functions, and on the use of long authentication keys. In this paper we propose a quantum authentication procedure that, making use of just one qubit as the authentication key, allows the authentication of binary classical messages in a secure manner.Comment: LaTeX, 6 page

Assessing Student Learning in Middle-Division Classical Mechanics/Math Methods

Reliable and validated assessments of introductory physics have been instrumental in driving curricular and pedagogical reforms that lead to improved student learning. As part of an effort to systematically improve our sophomore-level Classical Mechanics and Math Methods course (CM 1) at CU Boulder, we are developing a tool to assess student learning of CM 1 concepts in the upper-division. The Colorado Classical Mechanics/Math Methods Instrument (CCMI) builds on faculty-consensus learning goals and systematic observations of student difficulties. The result is a 9-question open-ended post-test that probes student learning in the first half of a two-semester classical mechanics / math methods sequence. In this paper, we describe the design and development of this instrument, its validation, and measurements made in classes at CU Boulder.Comment: 4 pages, 3 figures, 1 table; submitted to 2013 Proceedings of the Physics Education Research Conferenc

The effect of radiative gravitational modes on the dynamics of a cylindrical shell of counter rotating particles

In this paper we consider some aspects of the relativistic dynamics of a cylindrical shell of counter rotating particles. In some sense these are the simplest systems with a physically acceptable matter content that display in a well defined sense an interaction with the radiative modes of the gravitational field. These systems have been analyzed previously, but in most cases resorting to approximations, or considering a particular form for the initial value data. Here we show that there exists a family of solutions where the space time inside the shell is flat and the equation of motion of the shell decouples completely from the gravitational modes. The motion of the shell is governed by an equation of the same form as that of a particle in a time independent one dimensional potential. We find that under appropriate initial conditions one can have collapsing, bounded periodic, and unbounded motions. We analyze and solve also the linearized equations that describe the dynamics of the system near a stable static solutions, keeping a regular interior. The surprising result here is that the motion of the shell is completely determined by the configuration of the radiative modes of the gravitational field. In particular, there are oscillating solutions for any chosen period, in contrast with the "approximately Newtonian plus small radiative corrections" motion expectation. We comment on the physical meaning of these results and provide some explicit examples. We also discuss the relation of our results to the initial value problem for the linearized dynamics of the shell

A Highly Predictive Ansatz for Leptonic Mixing and CP Violation

We suggest a simple highly predictive ansatz for charged lepton and light neutrino mass matrices, based on the assumption of universality of Yukawa couplings. Using as input the charged lepton masses and light neutrino masses, the six parameters characterizing the leptonic mixing matrix $V_{PMNS}$, are predicted in terms of a single phase $\phi$, which takes a value around $\phi={\frac{\pi}{2}}$. Correlations among variuos physical quantities are obtained, in particular $V^{PMNS}_{13}$ is predicted as a function of ${\Delta}m^2_{21}$, ${\Delta}m^2_{31}$ and $\sin^2(\theta_{sol})$, and restricted to the range $0.167<|V^{PMNS}_{13}|<0.179$.Comment: 9 pages, 4 figure

Exploring the IT usage in SMEs from New Zealand, Columbia and Chile using action-research methodology

The theory on the adoption and use of information technology (IT) in small and medium enterprises (SMEs) is abundant. However, methodologically speaking, action-research (AR) has been little explored as a method of construction of this theory, despite the use of this methodology could improve understanding of how SMEs use IT. Therefore, we researched the use of IT in SMEs using a methodology adapted from AR. The methodology was tested in companies from New Zealand, Colombia and Chile. The use of this methodology was well evaluated by the top management of SMEs, in fact, the recommendations coming from the analysis were well received by the management of participants. These results are auspicious regarding the use of AR in SMEs and could help encourage other researchers to use this methodology, which remains little used in information systems research