878 research outputs found
Channelization architecture for wide-band slow light in atomic vapors
We propose a ``channelization'' architecture to achieve wide-band
electromagnetically induced transparency (EIT) and ultra-slow light propagation
in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong,
resonant ``pump'' laser on the atomic medium, which allows slow and
unattenuated propagation of a weaker ``signal'' beam, but only when a
two-photon resonance condition is satisfied. Our wideband architecture is
accomplished by dispersing a wideband signal spatially, transverse to the
propagation direction, prior to entering the atomic cell. When particular
Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic
field with a linear gradient such that the two-photon resonance condition is
satisfied for each individual frequency component. Because slow light is a
group velocity effect, utilizing differential phase shifts across the spectrum
of a light pulse, one must then introduce a slight mismatch from perfect
resonance to induce a delay. We present a model which accounts for diffusion of
the atoms in the varying magnetic field as well as interaction with levels
outside the ideal three-level system on which EIT is based. We find the maximum
delay-bandwidth product decreases with bandwidth, and that delay-bandwidth
product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a
large improvement over the ~1 MHz bandwidths in conventional slow light systems
and could be of use in signal processing applications.Comment: Published in SPIE Proceedings, Photonics West 2005 (San Jose, CA,
Jan. 22-27, 2005
Lead Us Not Into Translation: Notes Toward a Theoretical Foundation for Asian Studies
I begin this work with a simple question. Why is it impossible to imagine, much less write, a work like Michel Foucault's Discipline and Punish within Asian area studies? The impossibility I am referring to is not of content but of form. It is not just about writing such a text but about having it read as something more than a description; having it read for its theoretical significance more generally. That is to say, it is about the impossibility of writing a work that is principally of a theoretical nature but that is empirically and geographically grounded in Asia rather than in Europe or America. Why is it that, when it comes to Asian area studies, whenever âtheoryâ is invoked, it is invariably understood to mean âapplied theoryâ and assumed to be of value only insofar as it helps tell the story of the ârealâ in a more compelling way?
To some extent, what follows is an attempt to explain historically how Western area studies on Asia came to appreciate theory in this limited and limiting way. At the same time, as I began to investigate the history and prehistory of this diaphanous field, I began to recognize the possibilities of a very different form of area studies that could have emerged had different sets of pressures pushed it in a slightly different direction. This essay is therefore an attempt to recuperate these now forgotten possibilities and to build on them in order to produce a different way of seeing, writing, and theorizing Asian area studies
The Square: A Political Anthropology of the Built Environment
Beginning in Tian'anmen Square at dawn, this paper traces the political cosmologies of China through the built environment of Beijing. The diagnostic value of the built environment is revealed in its ability to help us navigate through the history of various political cosmologies that have informed the building and rebuilding of this city. From dynastic times when Celestial power was driven by the flow of 'qi' though the 'toppling' of the city axis and the imposition of another socialist cosmology and then onto the phantasmagoric showpieces of the economic miracle, the built environment becomes an archeological site of politics, revealing a way of seeing politics that is ethnographic and concerned with the everyday
Observation of Quantum Shock Waves Created with Ultra Compressed Slow Light Pulses in a Bose-Einstein Condensate
We have used an extension of our slow light technique to provide a method for
inducing small density defects in a Bose-Einstein condensate. These
sub-resolution, micron-sized defects evolve into large amplitude sound waves.
We present an experimental observation and theoretical investigation of the
resulting breakdown of superfluidity. We observe directly the decay of the
narrow density defects into solitons, the onset of the `snake' instability, and
the subsequent nucleation of vortices.Comment: 15 pages, 5 figure
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Preliminary Geologic Description Mobil Producing G.E. Cargill No.14
Two intervals of the Travis Peak Formation were cored in the Mobil Producing Cargill No. 14 well, Waskom field, Harrison County, Texas. Core was recovered from 5,903.0 to 5,960.4 ft and from 6,148.0 to 6,297.1 ft. The top of the Travis Peak is at 5,901 ft (log depth), so the core begins close to the top of the formation.Bureau of Economic Geolog
Detecting changes to sub-diffraction objects with quantum-optimal speed and accuracy
Detecting if and when objects change is difficult in passive sub-diffraction
imaging of dynamic scenes. We consider the best possible tradeoff between
responsivity and accuracy for detecting a change from one arbitrary object
model to another in the context of sub-diffraction incoherent imaging. We
analytically evaluate the best possible average latency, for a fixed false
alarm rate, optimizing over all physically allowed measurements of the optical
field collected by a finite 2D aperture. We find that direct focal-plane
detection of the incident optical intensity achieves sub-optimal detection
latencies compared to the best possible average latency, but that a three-mode
spatial-mode demultiplexing measurement in concert with on-line statistical
processing using the well-known CUSUM algorithm achieves this quantum limit for
sub-diffraction objects. We verify these results via Monte Carlo simulation of
the change detection procedure and quantify a growing gap between the
conventional and quantum-optimal receivers as the objects are more and more
diffraction-limited.Comment: 4 pages, 3 figure
Lead Us Not into Translation: Notes Toward a Theoretical Foundation for Asian Studies
I begin this work with a simple question. Why is it impossible to imagine, much less write, a work like Michel Foucaultâs Discipline and Punish within Asian area studies? The impossibility I am referring to is not of content but of form. It is not just about writing such a text but about having it read as something more than a description; having it read for its theoretical signiïŹcance more generally. That is to say, it is about the impossibility of writing a work that is principally of a theoretical nature but that is empirically and geographically grounded in Asia rather than in Europe or America. Why is it that, when it comes to Asian area studies, whenever âtheoryâ is invoked, it is invariably understood to mean âapplied theoryâ and assumed to be of value only insofar as it helps tell the story of the ârealâ in a more compelling way? To some extent, what follows is an attempt to explain historically how Western area studies on Asia came to appreciate theory in this limited and limiting way. At the same time, as I began to investigate the history and prehistory of this diaphanous ïŹeld, I began to recognize the possibilities of a very different form of area studies that could have emerged had different sets of pressures pushed it in a slightly different direction. This essay is therefore an attempt to recuperate these now forgotten possibilities and to build on them in order to produce a different way of seeing, writing, and theorizing Asian area studies.Je commence cet article par une simple question. Pourquoi est-il impossible dâimaginer, encore moins dâĂ©crire, une Ćuvre comme Surveiller et Punir au sein des Etudes asiatiques ? LâimpossibilitĂ© Ă laquelle je me rĂ©fĂšre nâest pas liĂ©e au fond mais Ă la forme. Il ne sâagit pas seulement dâĂ©crire un tel texte mais de le faire lire comme quelque chose qui soit plus quâune description ; le faire lire aussi pour sa portĂ©e thĂ©orique. Il sâagit de lâimpossibilitĂ© dâĂ©crire une Ćuvre qui serait de nature essentiellement thĂ©orique mais qui, empiriquement et gĂ©ographiquement, serait basĂ©e en Asie plutĂŽt quâen Europe ou en AmĂ©rique. Pourquoi donc la thĂ©orie, lorsquâil sâagit des Etudes asiatiques, est invariablement comprise comme une « thĂ©orie appliquĂ©e » dont la valeur ajoutĂ©e repose sur sa capacitĂ© Ă raconter lâhistoire du « rĂ©el » dâune maniĂšre plus convaincante ?Dans une certaine mesure, ce qui suit est une tentative pour expliquer historiquement comment, en Occident, les Area studies sur lâAsie en sont venues Ă comprendre la thĂ©orie de cette maniĂšre limitĂ©e et limitative. En mĂȘme temps, lorsque jâai commencĂ© Ă Ă©tudier lâhistoire et la prĂ©histoire de ce champ diaphane, jâai pu apercevoir les possibilitĂ©s dâune forme trĂšs diffĂ©rente dâĂ©tudes rĂ©gionales qui auraient pu Ă©merger si diffĂ©rents ensembles de pressions lâavait poussĂ©e dans une direction lĂ©gĂšrement diffĂ©rente. Cet essai est donc une tentative pour rĂ©cupĂ©rer ces possibilitĂ©s dĂ©sormais oubliĂ©es et construire, sur ces bases, une autre maniĂšre de voir, Ă©crire et thĂ©oriser les Etudes asiatiques
Cultural Revolution as Method
This paper treats the Chinese Cultural Revolution as a means by which to open on to a more affective approach to the question of the political. It examines one piece of art-technology of that period and shows the way it intuitively worked within the fluidity of power to produce political intensity. This one technology is a microcosm of the Cultural Revolution notion of the political that was built around an attempt to channel and harness affective power towards revolutionary ends. Both because it attempts to direct the political through the affective dimension and because its methods of doing so resembled contemporary art practices, this paper opens on to the possibilities of a method based on an art rather than a science of the political
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