2,305 research outputs found
The Kondo Effect in Non-Equilibrium Quantum Dots: Perturbative Renormalization Group
While the properties of the Kondo model in equilibrium are very well
understood, much less is known for Kondo systems out of equilibrium. We study
the properties of a quantum dot in the Kondo regime, when a large bias voltage
V and/or a large magnetic field B is applied. Using the perturbative
renormalization group generalized to stationary nonequilibrium situations, we
calculate renormalized couplings, keeping their important energy dependence. We
show that in a magnetic field the spin occupation of the quantum dot is
non-thermal, being controlled by V and B in a complex way to be calculated by
solving a quantum Boltzmann equation. We find that the well-known suppression
of the Kondo effect at finite V>>T_K (Kondo temperature) is caused by inelastic
dephasing processes induced by the current through the dot. We calculate the
corresponding decoherence rate, which serves to cut off the RG flow usually
well inside the perturbative regime (with possible exceptions). As a
consequence, the differential conductance, the local magnetization, the spin
relaxation rates and the local spectral function may be calculated for large
V,B >> T_K in a controlled way.Comment: 9 pages, invited paper for a special edition of JPSJ "Kondo Effect --
40 Years after the Discovery", some typos correcte
Containing, embracing and hyper-activating Britishness: British-based foreign-owned firms
There are in the UK ownership forms different to the characteristics of Britishness – British-based foreign-owned firms where dominant owners may have differentiated control interests. These may contain, that is, override, national institutional characteristics embedded in a particular national capitalism. Accordingly, separating the agency of these firms from presumed business system structures may reveal how diverse patterns of firm ownership – those associated with British-based foreign-owned firms – can inform dynamic ownership developments in British capitalism which contain and hyper-activate Britishness. The article theorizes British-based foreign-owned firms and provides empirical detail on how ownership characteristics influence financial commitment and strategic control in 10 of these firms
Contested resources: unions, employers, and the adoption of new work practices in US and UK telecommunications
The pattern of adoption of high-performance work practices has been explained in terms of strategic contingency and in terms of union presence. We compare the post-deregulation/privatization changes in work practice at AT&T, Bell Atlantic and British Telecom. On the basis of these cases, we argue that the choice of new work practices should be understood as a consequence not only of the company's resources or changes in its environment, nor of a simple union presence, but also as a consequence of the practices' effects on union power, the nature of the union's engagement, and the union's strategic choices
Tunneling into Current-Carrying Surface States of High T Superconductors
Theoretical results for the ab-plane tunneling conductance in the d-wave
model for high Tc superconductors are presented. The d-wave model predicts
surface bound states below the maximum gap. A sub-dominant order parameter,
stabilized by the surface, leads to a splitting of the zero-bias conductance
peak (ZBCP) in zero external field and to spontaneous surface currents. In a
magnetic field screening currents shift the quasiparticle bound state spectrum
and lead to a voltage splitting of the ZBCP that is linear in H at low fields,
and saturates at a pairbreaking critical field of order 3 Tesla. Comparisons
with recent experimental results on Cu/YBCO junctions are presented.Comment: 4 pages in a RevTex (3.0) file plus 3 Figures in PostScript. To
appear in Phys. Rev. Let
Human resource management–well‐being–performance research revisited:Past, present, and future
The authors provide an up‐to‐date theoretically based qualitative review of research dealing with the relationship between HRM, employee well‐being, and individual/organisational performance (HRM‐WB‐IOP research). The review is based on a systematic critical analysis of all HRM‐WB‐IOP studies (N = 46) published in 13 core HRM and management journals in the 2000 to 2018 period. The authors first identify different theoretical models of the HRM‐WB‐IOP relationship, which they then use to map research in the area. The results show that mutual gains conceptualisations play a dominant role in extant HRM‐WB‐IOP research, at the expense of alternative conflicting outcomes and mutual losses models, which are also shown to receive very limited empirical support across the 46 studies. As part of this mapping exercise, the authors identify important knowledge gaps in the area and conclude by setting out a number of key recommendations for future research to address these gaps
Teams between Neo-Taylorism and Anti-Taylorism
The concept of teamworking is the product of two distinct
developments. One: a neo-
Tayloristic form of organization of work, of which Toyota has shown
that it can be very profitable, was
packaged and reframed to make it acceptable to the Western public.
Two: anti-Tayloristic ways of
organizing work, inspired by ideals of organizational democracy,
were relabeled to make these
acceptable to profit-oriented managers.
Drawing on empirical research in Scandinavia, Germany, The
Netherlands and the UK, as
well as on published case studies of Japanese companies, the paper
develops a neo-Tayloristic and an
anti-Tayloristic model of teamworking.
Key concerns in the teamworking literature are intensification of
work and the use of shop
floor autonomy as a cosmetic or manipulative device. Indeed, all the
features of neo-Tayloristic
teamworking are geared towards the intensification of work. However,
one of the intensification
mechanisms, the removal of Tayloristic rigidities in the division of
labor, applies to anti-Tayloristic
teamworking as well. This poses a dilemma for employee
representatives. In terms of autonomy, on the
other hand, the difference between neo-Tayloristic and
anti-Tayloristic teamworking is real.
In anti-Tayloristic teamworking, there is no supervisor inside the
team. The function of
spokesperson rotates. All team members can participate in
decision-making. Standardization is not
relentlessly pursued; management accepts some measure of worker
control. There is a tendency to
alleviate technical discipline, e.g. to find alternatives for the
assembly line. Buffers are used.
Remuneration is based on proven skill level; there are no group
bonuses.
In contrast, in neo-Tayloristic teamworking, a permanent supervisor
is present in the team as
team leader. At most, only the team leader can participate in
decision-making. Standardization is
relentlessly pursued. Management prerogatives are nearly unlimited.
Job designers treat technical
discipline, e.g. short-cycled work on the assembly line, as
unproblematic. There are no buffers. A
substantial part of wages consists of individual bonuses based on
assessments by supervisors on how
deeply workers cooperate in the system. Group bonuses are also
given.
The instability and vulnerability of anti-Tayloristic teamworking
imply that it can only
develop and flourish when managers and employee representatives put
determined effort into it. The
opportunity structure for this contains both economic and political
elements. In mass production, the
economic success of Toyota, through skillful mediation by management
gurus, makes the opportunity
structure for anti-Tayloristic teamworking relatively unfavorable
Theory of Scanning Tunneling Spectroscopy of a Magnetic Adatom on a Metallic Surface
A comprehensive theory is presented for the voltage, temperature, and spatial
dependence of the tunneling current between a scanning tunneling microscope
(STM) tip and a metallic surface with an individual magnetic adatom. Modeling
the adatom by a nondegenerate Anderson impurity, a general expression is
derived for a weak tunneling current in terms of the dressed impurity Green
function, the impurity-free surface Green function, and the tunneling matrix
elements. This generalizes Fano's analysis to the interacting case. The
differential-conductance lineshapes seen in recent STM experiments with the tip
directly over the magnetic adatom are reproduced within our model, as is the
rapid decay, \sim 10\AA, of the low-bias structure as one moves the tip away
from the adatom. With our simple model for the electronic structure of the
surface, there is no dip in the differential conductance at approximately one
lattice spacing from the magnetic adatom, but rather we see a resonant
enhancement. The formalism for tunneling into small clusters of magnetic
adatoms is developed.Comment: 12 pages, 9 figures; to appear in Phys. Rev.
A Self-Consistent First-Principles Technique Having Linear Scaling
An algorithm for first-principles electronic structure calculations having a
computational cost which scales linearly with the system size is presented. Our
method exploits the real-space localization of the density matrix, and in this
respect it is related to the technique of Li, Nunes and Vanderbilt. The density
matrix is expressed in terms of localized support functions, and a matrix of
variational parameters, L, having a finite spatial range. The total energy is
minimized with respect to both the support functions and the elements of the L
matrix. The method is variational, and becomes exact as the ranges of the
support functions and the L matrix are increased. We have tested the method on
crystalline silicon systems containing up to 216 atoms, and we discuss some of
these results.Comment: 12 pages, REVTeX, 2 figure
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