2,592 research outputs found
Dynamics in the Ising field theory after a quantum quench
We study the real-time dynamics of the order parameter . Our main result is the development of
a method for treating divergences associated with working directly in the field
theory limit. We recover the scaling limit of the corresponding result by
Calabrese et al. [Phys. Rev. Lett. \textbf{106}, 227203 (2011)], which was
obtained for the lattice model. Our formalism generalizes to integrable quantum
quenches in other integrable models
How norms can generate conflict
Norms play an important role in establishing social order. The current literature focuses on the emergence, maintenance and impact of norms with regard to coordination and cooperation. However, the issue of norm-related conflict deserves more attention. We develop a general theory of "normative conflict" by differentiating between two different kinds of conflict. The first results from distinct expectations of which means should be chosen to fulfil the norm, the second from distinct expectations of how strong the norm should restrain the self-interest. We demonstrate the empirical relevance of normative conflict in an experiment that applies the "strategy method" to the ultimatum game. Our data reveal normative conflict among different types of actors, in particular among egoistic, equity, equality and "cherry picker" types.Social norms, normative conflict, cooperation, ultimatum game, strategy method, equity
Supersymmetry in the Majorana Cooper-Pair Box
Over the years, supersymmetric quantum mechanics has evolved from a toy model
of high energy physics to a field of its own. Although various examples of
supersymmetric quantum mechanics have been found, systems that have a natural
realization are scarce. Here, we show that the extension of the conventional
Cooper-pair box by a 4pi-periodic Majorana-Josephson coupling realizes
supersymmetry for certain values of the ratio between the conventional
Josephson and the Majorana- Josephson coupling strength. The supersymmetry we
find is a "hidden" minimally bosonized supersymmetry that provides a
non-trivial generalization of the supersymmetry of the free particle and relies
crucially on the presence of an anomalous Josephson junction in the system. We
show that the resulting degeneracy of the energy levels can be probed directly
in a tunneling experiment and discuss the various transport signatures. An
observation of the predicted level degeneracy would provide clear evidence for
the presence of the anomalous Josephson coupling.Comment: 10 pages, 5 figure
Quantum quench in the sine-Gordon model
We consider the time evolution in the repulsive sine-Gordon quantum field
theory after the system is prepared in a particular class of initial states. We
focus on the time dependence of the one-point function of the semi-local
operator . By using two different methods
based on form-factor expansions, we show that this expectation value decays to
zero exponentially, and we determine the decay rate by analytical means. Our
methods generalise to other correlation functions and integrable models.Comment: 41 pages, 1 figure, some typos correcte
Augmenting Biogas Process Modeling by Resolving Intracellular Metabolic Activity
The process of anaerobic digestion in which waste biomass is transformed to methane by complex microbial communities has been modeled for more than 16 years by parametric gray box approaches that simplify process biology and do not resolve intracellular microbial activity. Information on such activity, however, has become available in unprecedented detail by recent experimental advances in metatranscriptomics and metaproteomics. The inclusion of such data could lead to more powerful process models of anaerobic digestion that more faithfully represent the activity of microbial communities. We augmented the Anaerobic Digestion Model No. 1 (ADM1) as the standard kinetic model of anaerobic digestion by coupling it to Flux-Balance-Analysis (FBA) models of methanogenic species. Steady-state results of coupled models are comparable to standard ADM1 simulations if the energy demand for non-growth associated maintenance (NGAM) is chosen adequately. When changing a constant feed of maize silage from continuous to pulsed feeding, the final average methane production remains very similar for both standard and coupled models, while both the initial response of the methanogenic population at the onset of pulsed feeding as well as its dynamics between pulses deviates considerably. In contrast to ADM1, the coupled models deliver predictions of up to 1,000s of intracellular metabolic fluxes per species, describing intracellular metabolic pathway activity in much higher detail. Furthermore, yield coefficients which need to be specified in ADM1 are no longer required as they are implicitly encoded in the topology of the speciesâ metabolic network. We show the feasibility of augmenting ADM1, an ordinary differential equation-based model for simulating biogas production, by FBA models implementing individual steps of anaerobic digestion. While cellular maintenance is introduced as a new parameter, the total number of parameters is reduced as yield coefficients no longer need to be specified. The coupled models provide detailed predictions on intracellular activity of microbial species which are compatible with experimental data on enzyme synthesis activity or abundance as obtained by metatranscriptomics or metaproteomics. By providing predictions of intracellular fluxes of individual community members, the presented approach advances the simulation of microbial community driven processes and provides a direct link to validation by state-of-the-art experimental techniques
Local density of states of 1D Mott insulators and CDW states with a boundary
We determine the local density of states (LDOS) of one-dimensional
incommensurate charge density wave (CDW) states in the presence of a strong
impurity potential, which is modeled by a boundary. We find that the CDW gets
pinned at the impurity, which results in a singularity in the Fourier transform
of the LDOS at momentum 2k_F. At energies above the spin gap we observe
dispersing features associated with the spin and charge degrees of freedom
respectively. In the presence of an impurity magnetic field we observe the
formation of a bound state localized at the impurity. All of our results carry
over to the case of one dimensional Mott insulators by exchanging the roles of
spin and charge degrees of freedom. We discuss the implications of our result
for scanning tunneling microscopy experiments on spin-gap systems such as
two-leg ladder cuprates and 1D Mott insulators
Data allocation and application for time-dependent vehicle routing in city logistics
In city logistics, service providers have to consider dynamics within logistics processes in order to
achieve higher schedule reliability and delivery flexibility. To this end, city logistics routing demands for
time-dependent travel time estimates and time-dependent optimization models. We consider the process
of allocation and application of empirical traffic data for time-dependent vehicle routing in city logistics
with respect to its usage. Telematics based traffic data collection and the conversion from raw empirical
traffic data into information models are discussed. A city logistics scenario points out the applicability of
the information models provided, which are based on huge amounts of real traffic data (FCD). Thus, the
benefits of time-dependent planning in contrast to common static planning methods can be demonstrated
How Norms Can Generate Conflict: An Experiment on the Failure of Cooperative Micro-motives on the Macro-level
Why does the adherence to norms not prevent conflict? While the current literature focuses on the emergence, maintenance and impact of norms with regard to cooperation, the issue of norm-related conflict deserves more attention. We develop a general game theoretical model of "normative conflictâ and explain how transaction failures on the macrolevel can result from cooperative motives on the microlevel. We differentiate between two kinds of conflict. The first results from distinct expectations regarding the way in which general normative obligations should be fulfilled, the second from distinct expectations as to how the norm should restrain actions based on self-interest. We demonstrate the empirical relevance of normative conflict in a version of the ultimatum game. Our data reveal widespread normative conflict among different types of actors - egoistic, equity, equality and cherry picker. Our findings demonstrate how cooperative intentions about how to divide a collectively produced good may fail to produce cooperative outcome
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