5,253 research outputs found
Symmetry characterization of the collective modes of the phase diagram of the quantum Hall state in graphene: Mean-field and spontaneously broken symmetries
We devote this work to the study of the mean-field phase diagram of the
quantum Hall state in bilayer graphene and the computation of the
corresponding neutral collective modes, extending the results of recent works
in the literature. Specifically, we provide a detailed classification of the
complete orbital-valley-spin structure of the collective modes and show that
phase transitions are characterized by singlet modes in orbital pseudospin,
which are independent of the Coulomb strength and suffer strong many-body
corrections from short-range interactions at low momentum. We describe the
symmetry breaking mechanism for phase transitions in terms of the valley-spin
structure of the Goldstone modes. For the remaining phase boundaries, we prove
that the associated exact symmetry existing at zero Zeeman energy and
interlayer voltage survives as a weaker mean-field symmetry of the Hartree-Fock
equations. We extend the previous results for bilayer graphene to the monolayer
scenario. Finally, we show that taking into account Landau level mixing through
screening does not modify the physical picture explained above.Comment: 44 pages, 10 figure
Has long become longer or short become shorter? Evidence from a censored quantile regression analysis of the changes in the distribution of U.S. unemployment duration
There is conflicting evidence regarding the recent evolution of unemployment duration in the U.S. In this study we rely on censored quantile regression methods to analyze the changes in the US unemployment duration distribution. We employed the decomposition method proposed by Machado and Mata (2003) to disentangle the contribution of the changes generated by the covariate distribution and by the conditional distribution and adapted it to a duration analysis framework.The data used in this inquiry are taken from the nationally representative Displaced Worker Survey of 1988 and 1998. We provide evidence that the unemployment duration distribution shifted leftward. The main driving force behind that shift was the sharp leftward move in the unemployment rate distribution. This force was partially counteracted by the ageing of the displaced population, the striking absence of impact from being displaced via a plant shutdown, and the higher sensitivity of unemployment duration to unemployment ratesQuantile Regression, Duration Analysis, Unemployment Duration, Counterfactual Decomposition
Violation of Cauchy-Schwarz inequalities by spontaneous Hawking radiation in resonant boson structures
The violation of a classical Cauchy-Schwarz (CS) inequality is identified as
an unequivocal signature of spontaneous Hawking radiation in sonic black holes.
This violation can be particularly large near the peaks in the radiation
spectrum emitted from a resonant boson structure forming a sonic horizon. As a
function of the frequency-dependent Hawking radiation intensity, we analyze the
degree of CS violation and the maximum violation temperature for a double
barrier structure separating two regions of subsonic and supersonic condensate
flow. We also consider the case where the resonant sonic horizon is produced by
a space-dependent contact interaction. In some cases, CS violation can be
observed by direct atom counting in a time-of-flight experiment. We show that
near the conventional zero-frequency radiation peak, the decisive CS violation
cannot occur.Comment: 10 pages, 6 figure
Entanglement and violation of classical inequalities in the Hawking radiation of flowing atom condensates
We consider a sonic black-hole scenario where an atom condensate flows
through a subsonic-supersonic interface. We discuss several criteria that
reveal the existence of nonclassical correlations resulting from the quantum
character of the spontaneous Hawking radiation. We unify previous general work
as applied to Hawking radiation analogs. We investigate the measurability of
the various indicators and conclude that, within a class of detection schemes,
only the violation of quadratic Cauchy-Schwarz inequalities can be discerned.
We show numerical results that further support the viability of measuring deep
quantum correlations in concrete scenarios.Comment: 15 pages, 6 figure
On Freezing Effects
This paper discusses the nature of Rizzi’s (2006, 2007) Criterial
Freezing, a mechanism yielding island effects on XPs moving into edge
positions within the Left Periphery to satisfy dedicated ‚criteria‛. Contrary
to Rizzi’s (2006) feature checking implementation, it is claimed that freezing,
as originally outlined in Chomsky (2000, 2001) Probe-Goal framework, is
restricted to purely formal features of the Case/agreement systems, criterial
formatives (e.g., [topic], [focus], [wh]) being irrelevant for minimality
purposes. Consequently, it is argued that Criterial Freezing is best regarded
as an interface constraint precluding XPs from being assigned multiple
interpretations of the same type, for legibility/convergence reasons
ultimately related to the Principle of Full Interpretation.Este trabajo aborda la naturaleza del proceso de Inmovilización de
Criterio establecido por Rizzi, un mecanismo que reivindica Efectos de isla
por parte de aquellos SSXX que se mueven a una posición de arista dentro
de la periferia izquierda para de esta forma satisfacer ‘criterios’ específicos.
A diferencia de la implementación llevada a cabo por Rizzi en su teoría de
validación de rasgos, se establece que la operación de Inmovilización, tal y
como se concibe inicialmente en el marco de trabajo Sonda-Meta de
Chomsky (2000, 2001) está limitado a rasgos puramente formales de los
sistemas de Caso/concordancia, por lo que los formativos de criterio (por
ejemplo, [tópico], [foco], [wh]) son irrelevantes desde un punto de vista
minimalista. Por lo tanto, se establece que el proceso de Inmovilización de
Criterio ha de ser considerado como una limitación propia de la interfaz que
evita que los SSXX reciban interpretaciones múltiples del mismo tipo,
debiéndose en última instancia a razones de legibilidad/convergencia
relacionadas con el Principio de Interpretación Plena.Este artigo discute a natureza do Congelamento Criterial de Rizzi
(2006, 2007), um mecanismo que produz efeitos de ilha em XPs deslocados
para posições periféricas dentro da Periferia à Esquerda para satisfação de
«critérios» dedicados. Contrariamente à implementação da propriedade de
verificação de Rizzi (2006), afirma-se que o congelamento (como
originalmente concebido em Chomsky (2000, 2001) quadro Sonda-Alvo
restringe-se a propriedades puramente formais dos sistemas de
Caso/concordância, sendo formativos criteriais (por exemplo, [tópico], [foco],
[wh-]) irrelevantes para fins de minimalidade. Consequentemente, é
argumentado que o Congelamento Criterial é melhor concebido como um
interface de restrição impedindo a atribuição de múltiplas interpretações do
mesmo tipo a XPs, por razões de legitimidade/convergência relacionadas em
última instância com o Princípio da Interpretação Plena
Dynamic Workplace Design
The design of workplaces is often complex because it balances two opposing forces: on the one hand, innovation and creativity often involve teamwork processes and collaboration, occurring in spaces which may then produce higher than normal noise levels. On the other hand, many work processes rely on individual work, which requires quiet spaces needed for concentration. Another complex issues that office design architects must address involves the ever changing nature of workplaces, either as part of short-term evolving daily activities or as part of the longer-term changes organizations have to bring to their managerial style in order to stay competitive and productive.
This thesis proposes an experimental methods of improving acoustic properties in open-plan offices using a two-fold approach: specific tailoring of acoustic panels and other devices used in as needed bases; and the arrangement of office layouts to better match the managerial profile of organizations in terms of autonomy and interaction.
This thesis develops and tests the hypothesis that the balance of visual connectivity and auditory privacy in the workplace through the creation of organized sound composing a focus-driven atmosphere will improve the efficiency of the collaborative workplace and its environment. By observing in detail the elements of sound, materiality and effective experimenting, the thesis incorporates a process allowing for the control of the sound in the workplace, and thus encouraging higher productivity in the office space. By studying an open office space that can offer surfaces it determines modifications depending on the qualities of the room. The open office must become a culture that can identify the issues within its wall and the most effective way to contra rest the loose of focus. The goal is to improve the process in which architecture creates a better functional office space for people to use. By referencing back to past work this thesis tackles this issue using tools and by gathering information from past attempts and precedents. Building a strong backbone for this process to work is key for the future investigation to endure.
This thesis develops the argument that introduces sound into architecture as the main goal. To better demonstrate the purpose of the thesis experiments that measures sound physically in the environment will be simulated and analyzed with digital tools that design into an existing space. The analyzed space is specifically an office space that way the result provides structure for the theorem and concept. The expected results are analyzed in order to prove that acoustic design is a major factor and it improves the efficiency in the workplace without disregarding visual connectivity
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