Coherent Ensemble Research Articles

'Fashion in undress': Clothing and Commodity Culture in Household Words

'Fashion in undress':Clothing and Commodity Culture in Household Words Catherine Waters (bio) In Little Dorrit, Dickens describes the motley group of 'nondescript messengers, go-betweens, and errand bearers' who congregate outside the Marshalsea prison each morning before the gates open in these terms: Such threadbare coats and trousers, such fusty gowns and shawls, such squashed hats and bonnets, such boots and shoes, such umbrellas and walking sticks, never were seen in Rag Fair. All of them wore the cast-off clothes of other men and women, were made up of patches and pieces of other people's individuality, and had no sartorial existence of their own proper.1 The miscellaneous clothing of the Marshalsea poor is marked by dispossession in a way that thwarts the establishment of identity. The haphazard combination of patched and misshapen garments produces a scene of undifferentiated poverty. While Mrs Clennam's worsted gloves and widow's dress serve to express her cold and embittered selfhood – 'There was a smell of black dye in the airless room, which the fire had been drawing out of the crape and stuff of the widow's dress for fifteen months' (27) – the marginality of the Marshalsea go-betweensis ironically emphasized by the fact that their clothing is so worn-outas to be beyond resale in the cast-off market. Not only do they lack a coherent ensemble, their garments are imbued with the traces of other lives, and their lack of 'sartorial existence' is a measure of their social occlusion. Dickens's description assumes a continuity between clothing and identity as normative only to call that assumption into question as part of the narrative's social critique. The idea of 'sartorial existence', or the lack thereof, in Little Dorrit, points to the more general function of clothing as a symbolic expression of identity in Victorian culture, as well as to its particular use in the nineteenth-century novel to define fictional character. Dress is a sign [End Page 26] replete with social meaning and value. As the most famous Victorian clothes-philosopher argues in Sartor Resartus, '"Society is founded upon Cloth"' and Carlyle uses clothing and its fetishism to expose the fabrications of authority in modern social and political institutions.2 The function of clothing as an expression of selfhood is a relatively recent and distinctively urban development, as theorists such as Richard Sennett have shown. The nineteenth-century expansion and fragmentation of city life produced new anxieties about the definition and interpretation of metropolitan identities. As public behaviour became 'a matter of observation, of passive participation, of a certain kind of voyeurism',3 the need to decode the more nuanced languages of an increasingly homogeneous urban dress found literary expression in the figure of the flâneur, that passionate observer of city life. In the crowded metropolitan milieu of strangers, clothing became invested with character, containing subtle markers of social differentiation. Fashion, as Elizabeth Wilson notes, originates 'in the early capitalist city',4 and as Peter Stallybrass reminds us, the example with which Marx begins his analysis of commodity fetishism in Capital is a coat.5 Marx tracks the coat and the linen of which it is made back through the transformations of the capitalist marketplace to identify the human labour that was appropriated in its making. Distinguishing between the use-value and the exchange-value of the coat, Marx demonstrates that the latter is created by the 'congelation' of human labour – consideredin the abstract – that was expended in its making and is therefore embodied in it. 'In this aspect,' he argues, 'the coat is a depositoryof value, but though worn to a thread, it does not let this fact show through.'6 Clothing has long been recognized as a key element used by nineteenth-century novelists to achieve that 'solidity of specification' associated by Henry James with narrative realism.7 More recently, cultural critics have linked the depiction of dress and other consumer goods in Dickens's novels to the emergence of commodity culturein the nineteenth century. The link is made by Murray Roston, for example, in Victorian Contexts (1996), where he argues more generally that the personification of the inanimate in Dickens's fiction can...

‘Fashion in undress’: Clothing and Commodity Culture inHousehold Words

The miscellaneous clothing of the Marshalsea poor is marked by dis possession in a way that thwarts the establishment of identity. The haphazard combination of patched and misshapen garments produces a scene of undifferentiated poverty. While Mrs Clennam’s worsted gloves and widow’s dress serve to express her cold and embittered selfhood – ‘There was a smell of black dye in the airless room, which the fire had been drawing out of the crape and stuff of the widow’s dress for fifteen months’ (27) – the marginality of the Marshalsea go-betweens is ironically emphasized by the fact that their clothing is so worn-out as to be beyond resale in the cast-off market. Not only do they lack a coherent ensemble, their garments are imbued with the traces of other lives, and their lack of ‘sartorial existence’ is a measure of their social occlusion. Dickens’s description assumes a continuity between clothing and identity as normative only to call that assumption into question as part of the narrative’s social critique. The idea of ‘sartorial existence’, or the lack thereof, in Little Dorrit, points to the more general function of clothing as a symbolic ex pression of identity in Victorian culture, as well as to its particular use in the nineteenth-century novel to define fictional character. Dress is a sign

The Need for a Multi-Disciplinary Approach

Like any science focusing on man (either as an individual or as part of a group), demography is faced with the need to develop a systematic approach: its units of observation (individual or collective) are multidimensional systems, whose many components define a single entity, which takes decisions, experiences events and influences its environment. The various disciplines as we currently know them are simply different points of view from which we observe these units. Economics, sociology, epidemiology and medicine, the disciplines closest to demography from a thematic perspective, all face the same dilemma: in order to explain the behaviour of the unit studied, all dimensions of that unit must be taken into account, and no single dimension considered as exclusive (or more important than the others).The need for a multidisciplinary (or, more precisely, systematic) approach is not, therefore, unique to demography. It is, perhaps, simply more apparent, more acute in this discipline, for two reasons that can be seen as constraints, but also as opportunities, in that they strengthen the imperative to move beyond the classical approach. The first reason is the need to take both micro and macro dimensions into account. Demography, which is based upon a macro approach to the study of populations, has only recently begun to concern itself with micro (individual) and meso (family) units. Bringing these strands together is quite clearly vital (although moves to do so were late in coming, as indeed was the micro approach itself, if one considers the history of the discipline).The second reason arises out of the fact that with time, the events of specific interest to the demographer have lost much of their essentially biological nature and are increasingly matters of individual choice. They are, however, events of great significance in the life of an individual - birth of a child, migration, family formation, death - which are not the result of merely circumstantial choices (or situations), but rather milestones on a long decision path (or life course). Many different elements come into play (individual and collective, economic and social, cultural and biological, etc.), and it is often impossible - perhaps also ill-advised - to attempt to determine the specific part played by each.A multidisciplinary approach is thus vital to progress in demography, just as the advent of longitudinal methods has proven to be in recent years for the reconstruction of processes whose unfolding, on an individual timescale, as on a historical timescale, leads to certain demographic choices and events. The same applies today for the simultaneous consideration of micro and macro (and/or meso) levels when interpreting demographic behaviour.A further constraint - or opportunity - is the relative inadequacy of the theoretical corpus of demography, which favours an approach based on empirical observation. Such an approach does not, of course, allow one to dispense with a conceptual framework for analysing a phenomenon. On the contrary, a clear and well-structured theoretical framework with which to organize the system of relations governing the phenomenon is absolutely essential, even when collecting the initial statistics that will subsequently serve to describe its evolution and properties. What is often lacking is the grouping of sectorial hypotheses and theories into one coherent ensemble to be expressly adopted by those undertaking and initiating research. In one respect, the caution with which demographers have always approached the construction of theories reflects the realism of a discipline that, to build bridges between social and biological sciences, has always needed to be wary of partial approaches and the inadequacy of simple theories to resolve the complexity of the object of study. But this circumspection is liable to become a growing hindrance, as it quite clearly runs counter to the process of theory testing-appraisal-refutation that has been a driving force for progress in other fields, thanks notably to the passionate debates it has sparked (though such debate has not always been free from ideology and prejudice) (Popper, 1999)(1). …

Baby universes in string theory

We argue that the holographic description of four-dimensional Bogomol'nyi-Prasad-Sommerfield black holes naturally includes multicenter solutions. This suggests that the holographic dual to the gauge theory is not a single $\mathrm{Ad}{\mathrm{S}}_{2}\ifmmode\times\else\texttimes\fi{}{S}^{2}$ but a coherent ensemble of them. We verify this in a particular class of examples, where the two-dimensional Yang-Mills theory gives a holographic description of the black holes obtained by branes wrapping Calabi-Yau cycles. Using the free fermionic formulation, we show that $O({e}^{\ensuremath{-}N})$ nonperturbative effects entangle the two Fermi surfaces. In an Euclidean description, the wave function of the multicenter black holes gets mapped to the Hartle-Hawking wave function of baby universes. This provides a concrete realization, within string theory, of effects that can be interpreted as the creation of baby universes. We find that, at least in the case we study, the baby universes do not lead to a loss of quantum coherence, in accord with general arguments.

The sting at the end of the tail: Model diagnostics of fine‐scale three‐dimensional structure of the cloud head

AbstractThis is the second in a series of papers on ‘the sting at the end of the tail’—a mesoscale region of potentially damaging surface winds that can occur close to the evaporating tip of a cloud head wrapped around the bent‐back front of an extratropical cyclone. In the first paper the sting phenomenon was identified from a purely observational study of the great storm of October 1987. In the present paper an observationally validated forecast run from a high‐resolution numerical weather prediction model is used to examine the evolving three‐dimensional structure of the sting phenomenon. It is shown that the damaging surface winds in the October 1987 storm were due to a well‐defined mesoscale ‘sting jet’ (SJ), identifiable as a coherent ensemble of trajectories originating in cloudy air at about 650 hPa. There is evidence of multiple mesoscale slantwise circulations, and the SJ appears to form within the descending part of these circulations. Air within the SJ descends to the 900 hPa level over a period of about 4 h, during which time it accelerates from less than 20 to above 45 m s−1 with extremes greater than 50 m s−1. Although the wet‐bulb potential temperature of air in the SJ remains constant during its descent to 900 hPa, evaporation leads to a reduction of up to 5 K or more in dry‐bulb potential temperature in some parts of the jet. The SJ is situated behind the primary cold front, and is distinct from the associated warm‐conveyor‐belt low‐level jet; it is also distinct from the cold‐conveyor‐belt low‐level jet which remains below and behind it as the SJ skirts the bent‐back front. © Crown copyright, 2005.

Long-range EEG phase synchronization during an arithmetic task indexes a coherent cortical network simultaneously measured by fMRI

An open question lies in whether or not distributed activities in the distant brain regions are integrated into a coherent ensemble for cognitive information processing. Long-range phase synchronization is often observed by scalp EEG measurements during cognitive tasks and is considered to provide a possible neural principle for the functional integration of distributed neural activities. Synchronization could be reflected at the neuron firing level or at the local field potential and could appear in the scalp EEG under certain conditions on neural spatial and temporal coherence. To examine if phase synchronization is concerned with the integration of distant regions, we proposed a method to extract brain activities associated with task-dependent phase synchronization by combining simultaneous fMRI and EEG. By applying this method in a mental arithmetic task, we found a dominant task-dependent increase of phase synchronization around 14 Hz (in beta frequency) across bilateral parietal sites that were associated with both negative and positive BOLD responses. Functional connectivity analyses of these regions demonstrated that an increase in hemispheric beta synchronization was associated with a linking between the cross-hemispheric regions (left angular gyrus and right superior parietal gyrus) and also among the anterior–posterior regions (right dorsolateral prefrontal cortex, putamen, and right superior temporal gyrus). These findings indicate that the positive BOLD regions (dorsolateral prefrontal cortex and superior parietal lobule) are linked with other negative BOLD regions. We also discussed the possible importance of beta synchronization in the formation of a working memory network.

Experimental demonstration of a phase-locked laser array using a self-Fourier cavity

A coherent phase-locked laser array has been experimentally demonstrated by combining the outputs of seven individual fiber lasers together in a self-Fourier cavity. By analyzing the interference fringes of the laser output in the far field of the array, a fringe visibility was measured of V=0.87, indicating a coherence of 0.73. The total output power of this laser array when operated as a coherent ensemble was 0.4watts.

Odessa Memories by Nicolas V. Iljine (review)

342 SEER, 83, 2, 2005 After a short concluding chapter, drawing together the strandsof the case for a 'cultural revolution', the volume is rounded off with a useful, though briefchronology, the footnotes to the text and a shortguide to furtherreading, which concentrates on the major English-language works on the reign. Cracraft'snotes assiduouslydirect the reader to a decent range of materials, in both Englishand Russian,contemporaryaccountsandmodern scholarship. Given the wide-ranging nature of the work and the intended readership,it is certainly understandable that the author would wish to keep footnotes to a minimum. Nevertheless,thereare some omissionswhich seem puzzling, given the relatively limited number of English-languageworks on this subject. For example, although reference is made to the proceedings of the Fifth International Conference of the Study Group on Eighteenth-CenturyRussia (Rome, I996), no mention is made of Lindsey Hughes's paper on Peter's sister, Natal'ia Alekseevna, in that volume when Cracraft discusses Petrine women all too briefly in his first chapter. Similarly, in his discussion of the backgroundto the Great Northern Warin the chapteron militaryreform,the reader is not directed to Robert Frost'sexcellent 7heNorthern Wars(London, 2000). However, leaving aside these minor quibbles, it is difficultto find fault with a very readable and concise overview of a complex reign. The choice of subjectsmeans that Cracraftis undoubtedly writing to his strengths,thereby opening his importantworkon Peter'sreign to a much wider audience. I have little doubt that thiswill be a usefuladdition to any course on Russian history or culture. School ofSlavonic andEastEuropean Studies PAUL KEENAN University College London lijine, Nicolas V. (ed.). Odessa Memories. A Samuel and Althea Stroum Book. University of Washington Press, Seattle, WA and London, 2003. lv + 144 pp. Illustrations. Notes.Bibliography. Index.$40-00: ?30.50. ODESSA MEMORIES is a beautifulbook, lovingly constructedby its editor and the production team at the University of Washington Press. It considers the commercial and cultural entrep6t of Odessa in the period between c. I88o and the Russian Revolution, seeking to recreate diverse strandsof its history through both text and image. The front cover, with its reproduction of a postcard of the Potemkin Staircase and its italicized title, combines with the book's unusualphysical dimensionsto make the readerfeel that he is actually holding an illustratedsouveniredition fromthe turnof the nineteenth century. The first nineteen pages of the book confirm this impression being, without any explanation, furtherreproductions of early twentieth-centurypostcards of Odessa;without doubt the book'spicturesare its greateststrength.Dozens of postcards, with their rich and vivid aquatint colours, appear in the work, together creating a picture of late imperial Odessa that is at once both highly romanticizedand hyper-real. When it comes to text, Odessa Memories is an altogether less well-conceived creation. There is no clear policy with regard to the annotation of the work's many pictures;atleasthalfhave no captionswhatsoever.This ismost irritating REVIEWS 343 in those caseswhere the image contains itsown caption in Russianand French (common in pre-Revolutionary postcards), explicitly informing the Anglophone readerthat he is missinga piece of information(e.g., pp. vi, vii, xi, xxx, 39-4I, 43-47). Worse still, Nicolas Jljine has only rarely cross-referenced textual discussions with pictures of particularbuildings or places, and even lessfrequentlyattemptedto place correspondingtext and pictureson the same page, leaving the readerto makethesebasicconnections forhimself.In certain respects,image and text tell differentstories:the book contains no fewer than sixteen picturesof Odessa's many resorts,beaches and hydropathicestablishments (hardlysurprisinggiven that many who bought postcardswere visiting the city as 'curists')but only two paragraphsof Oleg Gubar and Alexander Rozenboim's articleare devoted to describingthisobviouslysignificantaspect of Odessa life (pp. 105-06). Moreover, in a work that so clearly sets out to examine topographies,both actualand conceptual, it is a greatshame that the only map of Odessa has been consigned to the last page and is not signposted in the contents. The articles in the book a preface by Iljine (pp. xxxiii-xxxv), a short memoir by Bel Kaufman (pp. xlix-lv), a supposedly central chapter by Patricia Herlihy (pp. 3-37) and Gubar and Rozenboim's examination of 'Daily Life in Odessa' (pp. 49-I22)- are not a coherent ensemble, on the one hand representingconflicting genres...

Quantum Monte Carlo method for the ground state of many-boson systems

We formulate a quantum Monte Carlo (QMC) method for calculating the ground state of many-boson systems. The method is based on a field-theoretical approach, and is closely related to existing fermion auxiliary-field QMC methods which are applied in several fields of physics. The ground-state projection is implemented as a branching random walk in the space of permanents consisting of identical single-particle orbitals. Any single-particle basis can be used, and the method is in principle exact. We illustrate this method with a trapped atomic boson gas, where the atoms interact via an attractive or repulsive contact two-body potential. We choose as the single-particle basis a real-space grid. We compare with exact results in small systems and arbitrarily sized systems of untrapped bosons with attractive interactions in one dimension, where analytical solutions exist. We also compare with the corresponding Gross-Pitaevskii (GP) mean-field calculations for trapped atoms, and discuss the close formal relation between our method and the GP approach. Our method provides a way to systematically improve upon GP while using the same framework, capturing interaction and correlation effects with a stochastic, coherent ensemble of noninteracting solutions. We discuss various algorithmic issues, including importance sampling and the back-propagation technique for computing observables, and illustrate them with numerical studies. We show results for systems with up to N approximately 400 bosons.

Conditions and possible mechanism of condensation of e–h pairs in bulk GaAs at room temperature

AbstractA mechanism of the condensation of e–h pairs in bulk GaAs at room temperature, which has been observed earlier, is proposed. The point is that the photon assisted pairing happens in a system of electrons and holes that occupy energy levels at the very bottoms of the bands. Due to a very high e–h density, the destruction of the pairs and loss of coherence does not occur because almost all energy levels inside a 30–60 meV band from the bottom of the conduction band prove to be occupied. As a result, a coherent ensemble of composite bosons (paired electrons and holes) with the minimum possible energy appears. The lifetime of this strongly non‐equilibrium coherent e–h BCS‐like state is as short as a few hundred of femtoseconds. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Inequivalence of pure state ensembles for open quantum systems: the preferred ensembles are those that are physically realizable.

An open quantum system in steady state rho(ss) can be represented by a weighted ensemble of pure states rho(ss) = [equation: see text] in infinitely many ways. A physically realizable (PR) ensemble is one for which some continuous measurement of the environment will collapse the system into a pure state /psi(t)>, stochastically evolving such that the proportion of time for which /psi(t)> = /psi(k)> equals Weierstrass p(k). Some, but not all, ensembles are PR. This constitutes the preferred ensemble fact. We present the necessary and sufficient conditions for a given ensemble to be PR, and illustrate the method by showing that the coherent state ensemble is not PR for an atom laser.

An acoustic model of a laminar sand bed

It was postulated that a laminar sand bed may be modeled as an ensemble of randomly layered Biot media. The thickness of each layer was approximately half a grain diameter. The porosity variations in the vertical direction were matched to the mean and standard deviation of that of a structure of packed spherical grains. The effect of large-scale lateral variations in porosity was simulated by performing a coherent ensemble average of the acoustic output from several realizations of the randomly layered medium. The medium parameters were chosen to represent water-saturated sand. Specifically, the sand bed was modeled as bounded by a homogeneous water halfspace above, and a homogeneous poroelastic halfspace of equal average porosity below. Reflected and transmitted signals were computed. Coherent and random components of the reflected signal were calculated. The coherent parts were directly related to the reflected and the transmitted waves. Results showed significant differences between the modeled sand bed and an equivalent uniform Biot medium. In the modeled sand bed, the fast wave attenuation was found to be anisotropic, and a propagating slow wave was excited at most incident angles, except at normal incidence, which may explain the apparent failure to detect the slow wave of certain experiments.

Reply to the Comment on “Transient Anisotropy and Fragment Rotational Excitation in the Femtosecond Photodissociation of Triiodide in Solution”

Reply to the Comment on “Transient Anisotropy and Fragment Rotational Excitation in the Femtosecond Photodissociation of Triiodide in Solution”

Photoionization of neutral atoms in a Bose-Einstein condensate

A process of photoionization of neutral atoms composing a Bose-Einstein condensate is examined theoretically. It is shown that the coherent nature of the initial atomic ensemble can lead to a relatively large phase-space density of the fermionic products (electrons and ions) and, hence, to photoionization rate suppression. This effect may serve as an experimental tool for investigation of collective interactions in a highly non-equilibrium coherent ensemble of charged fermions.

Direct interferometric techniques for characterizing ultrashort optical pulses

The two-time nonstationary correlation function is defined and applied to the problem of characterizing pulses whose amplitude and phase vary randomly from pulse to pulse. Using a linear-systems approach developed in earlier work, four simple interferometric techniques for measuring this quantity are described and analyzed. We show that these four methods offer simple and direct algorithms for reconstructing the correlation function and, in the case of a single pulse or a coherent ensemble of pulses, return the electric field amplitude and phase.

Counter-counter-intuitive quantum coherence effects

The study of an ensemble of phase–coherent atoms has recently lead to interesting theoretical innovations and experimental demonstrations of counter–intuitive effects such as electromagnetically induced transparency (EIT), lasing without inversion (LWI), enhancement of index of refraction and ultra–large nonlinear susceptibility. In the present notes, we report a couple of new effects along these lines. In fact, it would be fair to call them surprises even in the repertoire of ‘counter–intuitive effects’, i.e. ‘counter–counter–intuitive effects’. Specifically, we will show that the LWI concept, which is based on quantum coherence, has a surprising counterpart in the classical physics of free electron laser operation. In other current work, we find that it is possible to ‘lock’ atoms in an excited state via atomic coherence. It is, by now, not surprising that such a phase–coherent ensemble can show holes or dark lines in the emission spectrum. It is surprising that we can lock atoms in an excited (normally decaying) state via atomic coherence and interference. Such a phase–coherent collection of atoms, i.e. ‘phaseonium’, is indeed a novel new state of matter.

Horizontal inhomogeneities and acoustic scattering by granular poroelastic ocean sediments

The effect of horizontal inhomogeneities in sediment properties on acoustic scattering is modeled as a problem of diffraction by random apertures over a randomly stratified medium, by numerical simulation. Apertures of varying geometries were investigated. The ocean sediment is modeled in two steps. (1) The granularity is modeled as an ensemble average of a randomly layered poroelastic material, in which each layer represented a granular material of a particular grain size, and the thickness of each layer was related to the associated grain size and porosity by a conservation-of-mass relationship. (2) Lateral variations are approximated by performing a coherent ensemble average of results from several realizations of the randomly stratified medium in which the incident and scattered sound wave enter and exit the sediment interface through an aperture. Poroelastic medium parameters were chosen to represent water-saturated sand. The mean and standard deviations of the grain-size distribution were chosen to match existing experimental data. Scattered signals were computed for a selection of aperture functions and at various grazing angles. The angular variations in the scattering strength were compared. [Work supported by ONR Code 321 OA.]

CLUSTERING IN A COUPLED MAP LATTICE

Normal chaotic activity and anomalous chaotic activity have been observed in a uniform coupled map lattice (CML). The former is stable providing a space-time complexity by intermittency of different primitive clusterings. The latter is metastable being a synchronous chaotic activity throughout the CML. Small disturbance destroys it and the CML returns itself to the normal chaotic activity. A transition to the anomalous chaotic activity is possible via a saddle-node bifurcation from a checkerboard state, i.e., from a coherent ensemble of 2-periodic oscillating sites throughout the lattice with the neighboring ones opposite in phases.

Angular variation in the simulated reflection and scattering properties of granular poroelastic ocean sediments.

Reflection and scattering properties of an inhomogeneous poroelastic medium were studied via numerical simulation. The inhomogeneous medium was modeled as an ensemble average of randomly layered poroelastic material. Each layer represented a granular material of a particular grainsize. The thickness of each layer was related to the associated grainsize and porosity by a conservation of mass relationship. Lateral variations in grainsize were approximated by performing a coherent ensemble average of results from several realizations of the randomly stratified medium. Poroelastic medium parameters were chosen to represent water‐saturated sand. The mean and standard deviation of the grainsize distribution were chosen to match existing experimental data in order to test the model. Specifically, the inhomogeneous medium was modeled as bounded by a homogeneous water half‐space on the source side, and a homogeneous poroelastic half‐space of equivalent average porosity on the other side. Reflected signals were computed for high‐frequency plane waves incident at various grazing angles. Coherent and random components of the reflected signal were calculated. The coherent part was related to the reflection coefficient. The random component was related to the scattering strength of the medium. Results were compared with existing experimental data. [Work supported by ONR.]

Tunneling of laser-generated free electrons in semiconductor double wells.

A theoretical study of the dynamics of free photogenerated carriers in resonance-biased asymmetric GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As double wells is presented. We consider a situation where photogeneration takes place on a subpicosecond time scale and, initially, produces a coherent ensemble of free electron-hole pairs in the wide well. The simultaneous thermalization and tunneling of electrons between the two wells is analyzed within the density matrix approach. The interplay between tunneling and Coulomb scattering is explored at several levels of approximation regarding free-carrier screening. We find that the Coulomb interaction represents an effective agent to destroy phase coherence and to damp out coherent charge oscillations in the system. Our calculations predict that, if the free-carrier Coulomb interaction provides the dominant dephasing mechanism in the system, coherent charge density oscillations associated with free carriers should persist up to electron sheet densities of about 3\ifmmode\times\else\texttimes\fi{}${10}^{10}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$. It is shown that, under present conditions, dynamic screening within the plasmon-pole approximation and static screening give virtually identical results.