Agile and Evm for the Dod: a Review of the Challenges and a New Approach to Solve them

Department of Defense (DoD) acquisitions must improve program performance while working within budgetary constraints. The DoD community shows an interest in utilizing Agile methodologies, but struggles to reap Agile\u27s benefits. They encountered challenges including the historically built up processes that enforce heavy-weight oversight; the outdated, manufacturing focused Work Breakdown Structures (WBS) provided in DoD Handbook: Work Breakdown Structures (WBS) for Defense Material Items (MIL-STD-881C); and the inability of the traditional waterfall based processes to accommodate iterative development. The author used the scientific method to review the documented issues encountered when using Agile on a DoD program within the constraints of Earned Value Management (EVM). The author developed the hypothesis that the currently available WBS options in MIL-STD-881C are in conflict with attempts to implement Agile software development methodologies and Agile Earned Value Management (AgileEVM) on DoD acquisition activities. Modifying MIL-STD-881C to include an iterative-based software development focused WBS would provide the DoD environment with a foundation to begin an overhaul of the current procedures and best practices to better support Agile methodologies and increase the adoption of Agile techniques. Based on the findings in this paper, additional research topics include: developing and defining the new WBS structure, determining what modifications are needed to other military standards, documented procedures, and best practices, and discussing the cultural changes needed to support and encourage greater use of Agile development methodologies in the DoD

Doctor of Philosophy in Physics

dissertationConsisting of a single two-dimensional layer of Carbon atoms arranged in a hexagonal lattice, graphene represents one of the most exciting recent developments in condensed matter physics. With novel electronic and mechancial properties, graphene not only has great potential with respect to technological applications, but also displays phenomena that typically appear in relativistic quantum field theory. The low-energy electronic excitations of graphene consist of two identical species of massless Dirac particles. Due to the small Fermi velocity, these particles are strongly coupled through the Coulomb interaction. Although various perturbative approaches have succeeded in elucidating many of the electronic properties of graphene, one would still like a nonperturbative study to address various questions. In particular, the spontaneous breaking of chiral symmetry in the presence of an external magnetic field, commonly known as magnetic catalysis, is one of these questions. Early studies of this phenomenon in model relativistic field theories have posited the mechanism to be universal. More recently, this mechanism of spontaneous symmetry breaking has been studied in low-dimensional condensed matter systems. Due to the strongly-coupled nature of the low-energy effective field theory of graphene, nonperturbative methods of lattice gauge theory can be used which are well suited to studying chiral symmetry breaking. Most notably used to study the theory of the strong interactions, quantum chromodynamics, these methods have proven successful in elucidating nonperturbative phenomena in cases where perturbative methods fail. In this thesis, using these methods, evidence in favor of magnetic catalysis in the graphene effective field theory will be presented

Lattice field theory study of magnetic catalysis in graphene

We discuss the simulation of the low-energy effective field theory (EFT) for graphene in the presence of an external magnetic field. Our fully nonperturbative calculation uses methods of lattice gauge theory to study the theory using a hybrid Monte Carlo approach. We investigate the phenomenon of magnetic catalysis in the context of graphene by studying the chiral condensate which is the order parameter characterizing the spontaneous breaking of chiral symmetry. In the EFT, the symmetry-breaking pattern is given by U(4) -\u3e U(2) x U(2). We also comment on the difficulty, in this lattice formalism, of studying the time-reversal-odd condensate characterizing the ground state in the presence of a magnetic field. Finally, we study the mass spectrum of the theory, in particular the Nambu-Goldstone mode as well as the Dirac quasiparticle, which is predicted to obtain a dynamical mass

Simulating Z2\mathbb{Z}_2 Lattice Gauge Theory with the Variational Quantum Thermalizer

The properties of strongly-coupled lattice gauge theories at finite density as well as in real time have largely eluded first-principles studies on the lattice. This is due to the failure of importance sampling for systems with a complex action. An alternative to evade the sign problem is quantum simulation. Although still in its infancy, a lot of progress has been made in devising algorithms to address these problems. In particular, recent efforts have addressed the question of how to produce thermal Gibbs states on a quantum computer. In this study, we apply a variational quantum algorithm to a low-dimensional model which has a local abelian gauge symmetry. We demonstrate how this approach can be applied to obtain information regarding the phase diagram as well as unequal-time correlation functions at non-zero temperature.Comment: 9 pages, 10 figure

Simulating Z 2 lattice gauge theory with the variational quantum thermalizer

The properties of strongly-coupled lattice gauge theories at finite density as well as in real time have largely eluded first-principles studies on the lattice. This is due to the failure of importance sampling for systems with a complex action. An alternative to evade the sign problem is quantum simulation. Although still in its infancy, a lot of progress has been made in devising algorithms to address these problems. In particular, recent efforts have addressed the question of how to produce thermal Gibbs states on a quantum computer. In this study, we apply a variational quantum algorithm to a low-dimensional model which has a local abelian gauge symmetry. We demonstrate how this approach can be applied to obtain information regarding the phase diagram as well as unequal-time correlation functions at non-zero temperature

Bridging the gap between numerics and experiment in free standing graphene

We report results of large-scale quantum Monte Carlo (QMC) simulations of graphene. Using cutting-edge algorithmic improvements, we are able to consider spatial volumes, corresponding to 20808 electrons, that allow us to access energy scales of direct relevance to experiments. Using constrained random phase approximation (cRPA) estimates of short-ranged interactions combined with a Coulomb tail, we are able to successfully confront numerical and experimental estimates of the Fermi velocity renormalization. These results and their comparison with perturbation theory not only show the non-Fermi liquid character of graphene, but also prove the importance of lattice-scale physics and higher-order perturbative corrections beyond RPA for the quantitative description of the experimental data for the Fermi velocity renormalization in suspended graphene.Comment: Higher quality low temperature numerical data added, clear-cut suggestions for further experiment