2,111 research outputs found
Across the borderlines - Coalitional feminist politics beyond identity and difference
First lines of the Introduction (as abstract not provided): Class and identity politics have long had a vexed relationship. Proponents of purist class politics have dismissed movements based on gender, race, and sexuality as needlessly divisive, or as anathema to class solidarity. For their part, feminists, critical race theorists and queer theorists have critiqued this form of class politics as unable to give voice to the multidimensional forms of oppression experienced by various social groups. While this debate has been raging for decades in both political groups and theoretical spaces, a resolution or compromise between these two extreme positions has not been established. However, to my mind, the problem is more pressing now than ever, as we reach a global point of unprecedented economic, environmental and humanitarian crises that demand of us novel and coordinated political responses. As Eleanor Robertson writes in the Spring 2017 issue of Australian literary journal Meanjin: Neoliberalism is running into its historical limits, exhausting its ability to stabilise capitalism and pacify those to whom it has doled out poverty and misery. An identity politics that is detached from material and historical questions cannot help us now; neither can faithfully repeating the left tactics of the twentieth century. The process of reconstituting something new, something that addresses the unique situation in which we find ourselves, has begun (Robertson 2017, 69). Robertson identifies the need for a new way of mediating between the polarities of class and identity. This can also be understood in a philosophical sense as a question about subjectivity - what is the relationship between politics and individual subjects' locations or experiences? What aspects of subjectivity should politics take into account? Where identity politics focuses on membership to social groups and the dynamics of power and oppression arising from such group memberships, Marxist politics provides a more material approach to thinking about the subject and her location vis-a'-vis the means of production. There is, ostensibly, a particular tension between the dominant feminist conception of identity - that espoused in theories of intersectional feminism - and a material approach to the subject of class politics. This subject resists assimilation into an intersectional framework, which treats class as only one element of oppression amongst many, and similarly into postmodern frameworks, which tend to prioritise the discursive or normative aspects of power over the material
Relating transition-state spectroscopy to standard chemical spectroscopic processes
© 2017 Elsevier B.V. Transition-state spectra are mapped out using generalized adiabatic electron-transfer theory. This simple model depicts diverse chemical properties, from aromaticity, through bound reactions such as isomerizations and atom-transfer processes with classic transition states, to processes often described as being “non-adiabatic”, to those in the “inverted” region that become slower as they are made more exothermic. Predictably, the Born-Oppenheimer approximation is found inadequate for modelling transition-state spectra in the weak-coupling limit. In this limit, the adiabatic Born-Huang approximation is found to perform much better than non-adiabatic surface-hopping approaches. Transition-state spectroscopy is shown to involve significant quantum entanglement between electronic and nuclear motion
Continuous measurement feedback control of a Bose-Einstein condensate using phase contrast imaging
We consider the theory of feedback control of a Bose-Einstein condensate
(BEC) confined in a harmonic trap under a continuous measurement constructed
via non-destructive imaging. A filtering theory approach is used to derive a
stochastic master equation (SME) for the system from a general Hamiltonian
based upon system-bath coupling. Numerical solutions for this SME in the limit
of a single atom show that the final steady state energy is dependent upon the
measurement strength, the ratio of photon kinetic energy to atomic kinetic
energy, and the feedback strength. Simulations indicate that for a weak
measurement strength, feedback can be used to overcome heating introduced by
the scattering of light, thereby allowing the atom to be driven towards the
ground state.Comment: 4 figures, 11 page
Ignorance is bliss: General and robust cancellation of decoherence via no-knowledge quantum feedback
A "no-knowledge" measurement of an open quantum system yields no information
about any system observable; it only returns noise input from the environment.
Surprisingly, performing such a no-knowledge measurement can be advantageous.
We prove that a system undergoing no-knowledge monitoring has reversible noise,
which can be cancelled by directly feeding back the measurement signal. We show
how no-knowledge feedback control can be used to cancel decoherence in an
arbitrary quantum system coupled to a Markovian reservoir that is being
monitored. Since no-knowledge feedback does not depend on the system state or
Hamiltonian, such decoherence cancellation is guaranteed to be general, robust
and can operate in conjunction with any other quantum control protocol. As an
application, we show that no-knowledge feedback could be used to improve the
performance of dissipative quantum computers subjected to local loss.Comment: 6 pages + 2 pages supplemental material, 3 figure
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