Lasing in Strong Coupling

An almost ideal thresholdless laser can be realized in the strong-coupling regime of light-matter interaction, with Poissonian fluctuations of the field at all pumping powers and all intensities of the field. This ideal scenario is thwarted by quantum nonlinearities when crossing from the linear to the stimulated emission regime, resulting in a universal jump in the second order coherence, which measurement could however be used to establish a standard of lasing in strong coupling.Comment: 5 pages, 2 figure

How sensitive is a neutrino factory to the angle θ13\theta_{13}?

We consider the impact of non-standard interactions of neutrinos (NSI) on the determination of neutrino mixing parameters at a neutrino factory using \pnu{e}\to\pnu{\mu} ``golden channels'' for the measurement of $\theta_{13}$. We show how a small residual NSI leads to a drastic loss in sensitivity in $\theta_{13}$, of up to two orders of magnitude. This can be somewhat overcome if two baselines are combined.Comment: 4 pages, 3 figure

Spontaneous, collective coherence in driven, dissipative cavity arrays

We study an array of dissipative tunnel-coupled cavities, each interacting with an incoherently pumped two-level emitter. For cavities in the lasing regime, we find correlations between the light fields of distant cavities, despite the dissipation and the incoherent nature of the pumping mechanism. These correlations decay exponentially with distance for arrays in any dimension but become increasingly long ranged with increasing photon tunneling between adjacent cavities. The interaction-dominated and the tunneling-dominated regimes show markedly different scaling of the correlation length which always remains finite due to the finite photon trapping time. We propose a series of observables to characterize the spontaneous build-up of collective coherence in the system.Comment: 9 pages, 4 figures, including supplemental material (with 4 pages, 1 figure). This is a shorter version with some modifications in the supplemental material (a gap in the proof was closed and calculations significantly generalized and improved

Strong-coupling of quantum dots in microcavities

We show that strong-coupling (SC) of light and matter as it is realized with quantum dots (QDs) in microcavities differs substantially from the paradigm of atoms in optical cavities. The type of pumping used in semiconductors yields new criteria to achieve SC, with situations where the pump hinders, or on the contrary, favours it. We analyze one of the seminal experimental observation of SC of a QD in a pillar microcavity [Reithmaier et al., Nature (2004)] as an illustration of our main statements.Comment: Substantially revised version. The major change is in the analysis of one of the seminal experiment of the field, that shows the excellent quantitative agreement with the theory. Full details, especially all concerning Fermi statistics (still present in previous versions), are now to be presented elsewhere. To be published in Phys. Rev. Lett. 101 (2008

An exploration of executive women's experiences of coaching and mentoring: an Interpretative Phenomenological Analysis study

The slow pace of women’s advancement to senior levels in organisations is an ongoing topical debate. Resolving this issue through appropriate developmental support interventions is the subject of much discussion. An understanding of the use of coaching and mentoring to address this individual, organisational and societal problem is, however, underresearched in a UK context, and more widely. In the coaching and mentoring literature there is limited research concerning the voice of the coachee/mentee and even less research relating to executive women. This study sought to address this deficiency and explore the experiences of executive women who have been coached and mentored, in order to gain an understanding of the role of these interventions and how they assisted the women’s development. Qualitative research was conducted using an Interpretative Phenomenological Analysis (IPA) methodology and involved semi-structured interviews with twelve executive women, all of whom worked at senior levels in UK organisations. The data were subsequently analysed using Smith, Flowers and Larkin’s (2009) interpretive framework. The findings highlight the positive impact of coaching and mentoring on the careers of the executive women in this study. Mentoring provided early career and psychosocial support, while coaching provided later support and challenge that encouraged the development of skills, authenticity and identity; aided coping with and adapting to the work environment; and in some cases assisted with broader life decisions. The participants’ subsequent commitment to coach and mentor others was a further outcome of this research. This study contributes not only to understanding the context of a coaching assignment involving executive women, the ‘experience’ of coaching and mentoring, and the importance of the coaching relationship, but also to the application of such learning to assist others. The implications of this research expand knowledge and provide new insights to add to the limited literature on coaching and mentoring executive women in the UK

Climbing the Jaynes-Cummings ladder by photon counting

We present a new method to observe direct experimental evidence of Jaynes--Cummings nonlinearities in a strongly dissipative cavity quantum electrodynamics system, where large losses compete with the strong light-matter interaction. This is a highly topical problem, particularly for quantum dots in microcavities where transitions from higher rungs of the Jaynes--Cummings ladder remain to be evidenced explicitly. We compare coherent and incoherent excitations of the system and find that resonant excitation of the detuned emitter make it possible to unambiguously evidence few photon quantum nonlinearities in currently available experimental systems.Comment: 4 pages, 4 figures (color online). Updated bb

On q-Deformed Supersymmetric Classical Mechanical Models

Based on the idea of quantum groups and paragrassmann variables, we presenta generalization of supersymmetric classical mechanics with a deformation parameter $q= \exp{\frac{2 \pi i}{k}}$ dealing with the $k =3$ case. The coordinates of the $q$-superspace are a commuting parameter $t$ and a paragrassmann variable $\theta$, where $$. The generator and covariant derivative are obtained, as well as the action for some possible superfields.Comment: No figures, 14 pages, Latex, revised versio

Finding the Higgs Boson through Supersymmetry

The study of displaced vertices containing two b--jets may provide a double discovery at the Large Hadron Collider (LHC): we show how it may not only reveal evidence for supersymmetry, but also provide a way to uncover the Higgs boson necessary in the formulation of the electroweak theory in a large region of the parameter space. We quantify this explicitly using the simplest minimal supergravity model with bilinear breaking of R-parity, which accounts for the observed pattern of neutrino masses and mixings seen in neutrino oscillation experiments.Comment: 7 pages, 7 figures. Final version to appear at PRD. Discussion and results were enlarge