1,002 research outputs found
A Pilot Using OverDrive: E-lending in Academic Law Libraries
E-books are not just for popular reading; legal publishers are entering the e-book market as well. Major publishers are launching e-book platforms and offering law libraries the opportunity to purchase both individual titles and collections of electronic books that they also offer in print. With increasing signs of a strong future for e-books, and possibly for e-lending as well, in spring 2012 Cornell Law Library decided to pilot OverDrive for the Cornell Law School community. By embarking on a pilot of the OverDrive service, we could test the waters of e-lending in a cost-efficient way that would not be prohibitive in terms of staff time and library resources. As consumers become more accustomed to e-books in general and e-lending specifically, our law school users are likely to expect their materials to be available similarly—and legal academic publishers are already showing signs of responding. Cornell University Law Library’s e-lending pilot shows that the law school community is open to this new model of access and lending
Non-commutative Quantum Mechanics in Three Dimensions and Rotational Symmetry
We generalize the formulation of non-commutative quantum mechanics to three
dimensional non-commutative space. Particular attention is paid to the
identification of the quantum Hilbert space in which the physical states of the
system are to be represented, the construction of the representation of the
rotation group on this space, the deformation of the Leibnitz rule accompanying
this representation and the implied necessity of deforming the co-product to
restore the rotation symmetry automorphism. This also implies the breaking of
rotational invariance on the level of the Schroedinger action and equation as
well as the Hamiltonian, even for rotational invariant potentials. For
rotational invariant potentials the symmetry breaking results purely from the
deformation in the sense that the commutator of the Hamiltonian and angular
momentum is proportional to the deformation.Comment: 21 page
The N=1 Supersymmetric Landau Problem and its Supersymmetric Landau Level Projections: the N=1 Supersymmetric Moyal-Voros Superplane
The N=1 supersymmetric invariant Landau problem is constructed and solved. By
considering Landau level projections remaining non trivial under N=1
supersymmetry transformations, the algebraic structures of the N=1
supersymmetric covariant non(anti)commutative superplane analogue of the
ordinary N=0 noncommutative Moyal-Voros plane are identified
Noncommutative quantum mechanics -- a perspective on structure and spatial extent
We explore the notion of spatial extent and structure, already alluded to in
earlier literature, within the formulation of quantum mechanics on the
noncommutative plane. Introducing the notion of average position and its
measurement, we find two equivalent pictures: a constrained local description
in position containing additional degrees of freedom, and an unconstrained
nonlocal description in terms of the position without any other degrees of
freedom. Both these descriptions have a corresponding classical theory which
shows that the concept of extended, structured objects emerges quite naturally
and unavoidably there. It is explicitly demonstrated that the conserved energy
and angular momentum contain corrections to those of a point particle. We argue
that these notions also extend naturally to the quantum level. The local
description is found to be the most convenient as it manifestly displays
additional information about structure of quantum states that is more subtly
encoded in the nonlocal, unconstrained description. Subsequently we use this
picture to discuss the free particle and harmonic oscillator as examples.Comment: 25 pages, no figure
Establishing the impact of powerful AGN on their host galaxies
Establishing the role of active galactic nuclei (AGN) during the formation of
galaxies remains one of the greatest challenges of galaxy formation theory.
Towards addressing this, we summarise our recent work investigating: (1) the
physical drivers of ionised outflows and (2) observational signatures of the
impact by jets/outflows on star formation and molecular gas content in AGN host
galaxies. We confirm a connection between radio emission and extreme ionised
gas kinematics in AGN hosts. Emission-line selected AGN are significantly more
likely to exhibit ionised outflows (as traced by the [O III] emission line) if
the projected linear extent of the radio emission is confined within the
spectroscopic aperture. Follow-up high resolution radio observations and
integral field spectroscopy of 10 luminous Type 2 AGN reveal moderate power,
young (or frustrated) jets interacting with the interstellar medium. We find
that these sources live in highly star forming and gas rich galaxies.
Additionally, by combining ALMA-derived dust maps with integral field
spectroscopy for eight host galaxies of z~2 X-ray AGN, we show that H-alpha
emission is an unreliable tracer of star formation. For the five targets with
ionised outflows we find no dramatic in-situ shut down of the star formation.
Across both of these studies we find that if these AGN do have a negative
impact upon their host galaxies, it must be happening on small (unresolved)
spatial scales and/or an observable galaxy-wide impact has yet to occur.Comment: Invited Contribution to IAU Symposium 359 (T. Storchi-Bergmann, R.
Overzier, W. Forman & R. Riffel, eds.
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