Nonvacuum pseudoparticles, quantum tunneling and metastability

It is shown that nonvacuum pseudoparticles can account for quantum tunneling and metastability. In particular the saddle-point nature of the pseudoparticles is demonstrated, and the evaluation of path-integrals in their neighbourhood. Finally the relation between instantons and bounces is used to derive a result conjectured by Bogomolny and Fateyev.Comment: Latex, 16 pages, no figure

Application of Instantons: Quenching of Macroscopic Quantum Coherence and Macroscopic Fermi-Particle Configurations

Starting from the coherent state representation of the evolution operator with the help of the path-integral, we derive a formula for the low-lying levels $E = \epsilon_0 - 2\triangle\epsilon cos (s+\xi)\pi$ of a quantum spin system. The quenching of macroscopic quantum coherence is understood as the vanishing of $cos (s+\xi)\pi$ in disagreement with the suppression of tunneling (i.e. $\triangle\epsilon = 0$) as claimed in the literature. A new configuration called the macroscopic Fermi-particle is suggested by the character of its wave function. The tunneling rate ($(2\triangle\epsilon)/(\pi)$) does not vanish, not for integer spin s nor for a half-integer value of s, and is calculated explicitly (for the position dependent mass) up to the one-loop approximation.Comment: 13 pages, LaTex, no figure

Quantum Tunneling and Phase Transitions in Spin Systems with an Applied Magnetic Field

Transitions from classical to quantum behaviour in a spin system with two degenerate ground states separated by twin energy barriers which are asymmetric due to an applied magnetic field are investigated. It is shown that these transitions can be interpreted as first- or second-order phase transitions depending on the anisotropy and magnetic parameters defining the system in an effective Lagrangian description.Comment: 18 pages, 7 figure

Instanton Induced Tunneling Amplitude at Excited States with the LSZ Method

Quantum tunneling between degenerate ground states through the central barrier of a potential is extended to excited states with the instanton method. This extension is achieved with the help of an LSZ reduction technique as in field theory and may be of importance in the study of macroscopic quantum phenomena in magnetic systems.Comment: 8 pages, LaTex, no figure

Significance of zero modes in path--integral quantization of solitonic theories with BRST invariance

The significance of zero modes in the path-integral quantization of some solitonic models is investigated. In particular a Skyrme-like theory with topological vortices in (1+2) dimensions is studied, and with a BRST invariant gauge fixing a well defined transition amplitude is obtained in the one loop approximation. We also present an alternative method which does not necessitate evoking the time-dependence in the functional integral, but is equivalent to the original one in dealing with the quantization in the background of the static classical solution of the non-linear field equations. The considerations given here are particularly useful in - but also limited to - the one-loop approximation.Comment: 16 pages, LaTe

Quantisation of 2D-gravity with Weyl and area-preserving diffeomorphism invariances

The constraint structure of 2D-gravity with the Weyl and area-preserving diffeomorphism invariances is analysed in the ADM formulation. It is found that when the area-preserving diffeomorphism constraints are kept, the usual conformal gauge does not exist, whereas there is the possibility to choose the so-called ``quasi-light-cone'' gauge, in which besides the area-preserving diffeomorphism invariance, the reduced Lagrangian also possesses the SL(2,R) residual symmetry. The string-like approach is applied to quantise this model, but a fictitious non-zero central charge in the Virasoro algebra appears. When a set of gauge-independent SL(2,R) current-like fields is introduced instead of the string-like variables, a consistent quantum theory is obtained.Comment: 14 pages, Latex fil

Recommendations From the International Consortium on Professional Nursing Practice in Long-Term Care Homes

AbstractIn response to the International Association of Gerontology and Geriatrics' global agenda for clinical research and quality of care in long-term care homes (LTCHs), the International Consortium on Professional Nursing Practice in Long Term Care Homes (the Consortium) was formed to develop nursing leadership capacity and address the concerns regarding the current state of professional nursing practice in LTCHs. At its invitational, 2-day inaugural meeting, the Consortium brought together international nurse experts to explore the potential of registered nurses (RNs) who work as supervisors or charge nurses within the LTCHs and the value of their contribution in nursing homes, consider what RN competencies might be needed, discuss effective educational (curriculum and practice) experiences, health care policy, and human resources planning requirements, and to identify what sustainable nurse leadership strategies and models might enhance the effectiveness of RNs in improving resident, family, and staff outcomes. The Consortium made recommendations about the following priority issues for action: (1) define the competencies of RNs required to care for older adults in LTCHs; (2) create an LTCH environment in which the RN role is differentiated from other team members and RNs can practice to their full scope; and (3) prepare RN leaders to operate effectively in person-centered care LTCH environments. In addition to clear recommendations for practice, the Consortium identified several areas in which further research is needed. The Consortium advocated for a research agenda that emphasizes an international coordination of research efforts to explore similar issues, the pursuit of examining the impact of nursing and organizational models, and the showcasing of excellence in nursing practice in care homes, so that others might learn from what works. Several studies already under way are also described