title: Two-state systems with non-Markovian thermal and squeezed quantum noise inputs

authors: Parkins, Andrew Scott

abstract: The effect of quantum noise on the two-state system is studied in the context of (i) coherent quantum tunnelling in a double-well system subject to low temperature quantum noise, and (ii) the two-level atom subject to finite bandwidth squeezed noise. Our approach to these problems is based on the adjoint equation, which describes the evolution of a quantum stochastic density operator. This equation is amenable to solution by ordinary stochastic methods, of which numerical simulation plays the most significant role in our calculations.
The dissipative double-well system is relevant to the search for macroscopic quantum coherence in superconducting quantum interference devices, and previous work, starting from a two-state model and using path integral methods, has established the so-called “noninteracting-blip approximation” as a central result. The adjoint equation, applied to this problem in the weak coupling limit, is shown to closely reproduce this result. The noninteracting-blip approximation entails a Markovian-type assumption about the noise, and, by means of stochastic simulation, we are able to check, and confirm, the validity of this assumption, even for the case of a zero-temperature bath.
Squeezed light, which has reduced quantum fluctuations in one quadrature phase, has been produced experimentally, and possible applications are under active consideration. Analyses of the effect of squeezed light on fundamental radiative processes in simple atoms have revealed interesting possibilities, most notably line-narrowing in the fluorescence spectrum. The original analyses in this field of research have been based on the assumption of broad bandwidth squeezing, and we review the primary results found in this limit. Also in this limit, we study in more detail the phenomenon of squeezed-light-induced photon echoes.
For broad bandwidth squeezing, line-narrowing in resonance fluorescence is restricted to the central fluorescence peak, while the Rabi sidebands exhibit broadening. We examine strongly driven resonance fluorescence for the case in which squeezing is confined to relatively small regions of frequency space about individual fluorescence peaks. It is shown that the noisy component associated with the unsqueezed quadrature phase can be effectively decoupled from the atomic dynamics, which allows narrowing to occur in all three peaks of the spectrum.
Finally, we address the practical problem of producing an effective coupling between an atom and a realistic three-dimensional squeezed field of modest angular spread. We show that this can be achieved, in principle, inside a microscopic plane mirror cavity, provided the injected squeezed field is suitably mode-matched to the cavity.

text: Two-state systems with non-Markovian thermal and squeezed quantum noise inputs The effect of quantum noise on the two-state system is studied in the context of (i) coherent quantum tunnelling in a double-well system subject to low temperature quantum noise, and (ii) the two-level atom subject to finite bandwidth squeezed noise. Our approach to these problems is based on the adjoint equation, which describes the evolution of a quantum stochastic density operator. This equation is amenable to solution by ordinary stochastic methods, of which numerical simulation plays the most significant role in our calculations.
The dissipative double-well system is relevant to the search for macroscopic quantum coherence in superconducting quantum interference devices, and previous work, starting from a two-state model and using path integral methods, has established the so-called “noninteracting-blip approximation” as a central result. The adjoint equation, applied to this problem in the weak coupling limit, is shown to closely reproduce this result. The noninteracting-blip approximation entails a Markovian-type assumption about the noise, and, by means of stochastic simulation, we are able to check, and confirm, the validity of this assumption, even for the case of a zero-temperature bath.
Squeezed light, which has reduced quantum fluctuations in one quadrature phase, has been produced experimentally, and possible applications are under active consideration. Analyses of the effect of squeezed light on fundamental radiative processes in simple atoms have revealed interesting possibilities, most notably line-narrowing in the fluorescence spectrum. The original analyses in this field of research have been based on the assumption of broad bandwidth squeezing, and we review the primary results found in this limit. Also in this limit, we study in more detail the phenomenon of squeezed-light-induced photon echoes.
For broad bandwidth squeezing, line-narrowing in resonance fluorescence is restricted to the central fluorescence peak, while the Rabi sidebands exhibit broadening. We examine strongly driven resonance fluorescence for the case in which squeezing is confined to relatively small regions of frequency space about individual fluorescence peaks. It is shown that the noisy component associated with the unsqueezed quadrature phase can be effectively decoupled from the atomic dynamics, which allows narrowing to occur in all three peaks of the spectrum.
Finally, we address the practical problem of producing an effective coupling between an atom and a realistic three-dimensional squeezed field of modest angular spread. We show that this can be achieved, in principle, inside a microscopic plane mirror cavity, provided the injected squeezed field is suitably mode-matched to the cavity.

year: 1990

title: Absolute Intensities of NH-Stretching Transitions in Dimethylamine and Pyrrole

authors: Miller, Benjamin J.

subjects: chemistry

abstract: Vibrational spectra of vapor-phase dimethylamine (DMA) and pyrrole have been recorded in the 1000 to 13000 cm–1 region using long path conventional spectroscopy techniques. We have focused on the absolute intensities of the NH-stretching fundamental and overtone transitions; ΔνNH = 1–4 regions for DMA and the ΔνNH = 1–3 regions for pyrrole. In the ΔνNH = 1–3 regions for DMA, evidence of tunneling splitting associated with the NH-wagging mode is observed. For DMA, the fundamental NH-stretching transition intensity is weaker than the first NH-stretching overtone. Also, the fundamental NH-stretching transition in DMA is much weaker than the fundamental transition in pyrrole. We have used an anharmonic oscillator local mode model with ab initio calculated local mode parameters and dipole moment functions at the CCSD(T)/aug-cc-pVTZ level to calculate the NH-stretching intensities and explain this intensity anomaly in DMA.

text: Absolute Intensities of NH-Stretching Transitions in Dimethylamine and Pyrrole Vibrational spectra of vapor-phase dimethylamine (DMA) and pyrrole have been recorded in the 1000 to 13000 cm–1 region using long path conventional spectroscopy techniques. We have focused on the absolute intensities of the NH-stretching fundamental and overtone transitions; ΔνNH = 1–4 regions for DMA and the ΔνNH = 1–3 regions for pyrrole. In the ΔνNH = 1–3 regions for DMA, evidence of tunneling splitting associated with the NH-wagging mode is observed. For DMA, the fundamental NH-stretching transition intensity is weaker than the first NH-stretching overtone. Also, the fundamental NH-stretching transition in DMA is much weaker than the fundamental transition in pyrrole. We have used an anharmonic oscillator local mode model with ab initio calculated local mode parameters and dipole moment functions at the CCSD(T)/aug-cc-pVTZ level to calculate the NH-stretching intensities and explain this intensity anomaly in DMA.

year: 2012

title: Claiming spaces: Prioritising Maaori worldview

authors: Penehira, Mera

subjects: Maori

abstract: Ohomairangi Trust was established as a provider of early intervention services in February 2002. It is funded and accredited by the Ministry of Education, and is the first Kaupapa Maaori based early intervention service to be accredited by the Ministry of Education. Essentially Ohomairangi was developed because of a need in the community for a service that could focus on developing and providing early intervention in a uniquely Maaori way, without the constraints of a crown agency. The Ohomairangi early intervention team has a commitment to supporting both the positive developments for Maaori within the Ministry of Education, and the continued independent research and development of Kaupapa Maaori services. The primary purpose of Ohomairangi is to develop and provide a Kaupapa Maaori based early intervention service across Taamaki Makaurau, which meets recommended practice guidelines. This evolves from a starting point of Kaupapa Maaori theory.

text: Claiming spaces: Prioritising Maaori worldview Ohomairangi Trust was established as a provider of early intervention services in February 2002. It is funded and accredited by the Ministry of Education, and is the first Kaupapa Maaori based early intervention service to be accredited by the Ministry of Education. Essentially Ohomairangi was developed because of a need in the community for a service that could focus on developing and providing early intervention in a uniquely Maaori way, without the constraints of a crown agency. The Ohomairangi early intervention team has a commitment to supporting both the positive developments for Maaori within the Ministry of Education, and the continued independent research and development of Kaupapa Maaori services. The primary purpose of Ohomairangi is to develop and provide a Kaupapa Maaori based early intervention service across Taamaki Makaurau, which meets recommended practice guidelines. This evolves from a starting point of Kaupapa Maaori theory.

year: 2008