Multi-Photon Multi-Channel Interferometry for Quantum Information Processing

This thesis reports advances in the theory of design, characterization and simulation of multi-photon multi-channel interferometers. I advance the design of interferometers through an algorithm to realize an arbitrary discrete unitary transformation on the combined spatial and internal degrees of freedom of light. This procedure effects an arbitrary $n_{s}n_{p}\times n_{s}n_{p}$ unitary matrix on the state of light in $n_{s}$ spatial and $n_{p}$ internal modes. I devise an accurate and precise procedure for characterizing any multi-port linear optical interferometer using one- and two-photon interference. Accuracy is achieved by estimating and correcting systematic errors that arise due to spatiotemporal and polarization mode mismatch. Enhanced accuracy and precision are attained by fitting experimental coincidence data to a curve simulated using measured source spectra. The efficacy of our characterization procedure is verified by numerical simulations. I develop group-theoretic methods for the analysis and simulation of linear interferometers. I devise a graph-theoretic algorithm to construct the boson realizations of the canonical SU$(n)$ basis states, which reduce the canonical subgroup chain, for arbitrary $n$. The boson realizations are employed to construct $\mathcal{D}$-functions, which are the matrix elements of arbitrary irreducible representations, of SU$(n)$ in the canonical basis. I show that immanants of principal submatrices of a unitary matrix $T$ are a sum of the diagonal $\mathcal{D}(\Omega)$-functions of group element $\Omega$ over $t$ determined by the choice of submatrix and over the irrep $(\lambda)$ determined by the immanant under consideration. The algorithm for $\mathrm{SU}(n)$ $\mathcal{D}$-function computation and the results connecting these functions with immanants open the possibility of group-theoretic analysis and simulation of linear optics.Comment: PhD thesis submitted and defended successfully at the University of Calgary. This thesis is based on articles arXiv:1403.3469, arXiv:1507.06274, arXiv:1508.00283, arXiv:1508.06259 and arXiv:1511.01851 with co-authors. 145 pages, 31 figures, 11 algorithms and 4 tables. Comments are welcom

Universal quantum computation with optical four-component cat qubits

We propose a teleportation-based scheme to implement a universal set of quantum gates with a four-component cat code, assisted by appropriate entangled resource states and photon number resolving detection. The four-component cat code features the ability to recover from single photon loss. Here, we propose a concrete procedure to correct the single photon loss, including detecting the single photon loss event and recovering the initial states. By concatenating with standard qubit error correcting codes, we estimate the loss threshold for fault-tolerant quantum computation and obtain a significant improvement over the two-component cat code.Comment: 5+22 pages, 5 figures, comments are welcom

Attachment accuracy of a novel prototype robotic rotary and investigation of two management strategies for incomplete milked quarters

Throughout 2009 and 2010, FutureDairy (Camden, NSW, Australia) was involved in testing a novel prototype robotic rotary (RR). The commercial version RR is expected to be capable of carrying out 90 milkings per hour. To achieve the high throughput the rotary rotates the cow to the cup attachment robot and then around the platform in a stop–start fashion. The robot does not remain with the cow during the entire milking process. When not all teat cups are attached during a milking session there is an opportunity for cows to be sent back to the waiting yard for a second milking attempt. The study presented here was designed to test whether or not the extension of the interval to a second milking attempt improved milking success of incompletely milked cows. It was expected that with an increased milking interval between the two subsequent milkings the changes to the udder conformation could positively affect the attachment success at the second attempt. The 1 h milking interval treatment (1 h) simulated cows being drafted directly back to the pre-milking waiting yard, whilst the 3 h milking interval treatment (3 h) was designed to simulate cows being drafted back after accessing post-milking supplementary feed on a feedpad. The results presented in this manuscript showed no significant difference between the frequencies of successful attachment in the second attempt between the 1 h and 3 h treatments indicating that a reasonable level of flexibility exists with management of incompletely milked cows and dairy layout designs. Milk production level affected the probability of success at second attempt, which was about 7.5 times higher in cows with an average milk production level greater than 19.3 kg than those with less than 10.8 kg. When looking at the total proportion of cows successfully milked after two attempts, it was found that successful milking was more likely in multiparous cows compared to primiparous cows. Highlights • We studied management options for incompletely milked cows on a robotic rotary. • Firstly cows returned to waiting yard with approx. 1 h interval between attempts. • Secondly cows returned to waiting yard via feed pad – approx. 3 h between attempts. • No difference found between 1 and 3 h intervals on attachment success. • Level of flexibility exists with management of incompletely milked cows. Keywords: Success-rate; Pasture based; Automatic milking system; Robotic rotary; DairyDairy Australia, DeLaval, Department of Primary Industries NSW and The University of Sydney

Zoonotic disease risk perceptions and infection control practices of Australian veterinarians: Call for change in work culture

This study was conducted to determine the perceptions of zoonotic disease risk among Australian veterinarians, the infection control practices they use to protect themselves from zoonotic diseases, and the factors influencing their use of these protective practices. A questionnaire was designed and piloted prior to its administration to veterinarians at the annual Australian Veterinary Association Conference in May 2011. The questionnaire comprised 21 closed, semi-closed and open questions. Data from the questionnaire were analyzed using ordinal logistic regression analyses to determine significant factors for veterinarians’ use of personal protective equipment (PPE). A total of 344 veterinarians completed the questionnaire of which 63.7% were women, 63.2% worked in small/companion animal practice, and 79.9% worked in private veterinary practice. Of the respondents, 44.9% reported contracting a zoonosis during their careers with 19.7% reporting a suspected case and 25.2% reporting a confirmed incidence. Around 40–60% of veterinarians perceived exposure to zoonosis likely or very likely in a variety of situations. With reference to current national industry guidelines, the reported use of PPE was less than “adequate” for most scenarios except for performing postmortems, surgery or dental procedures. No PPE was used by 60–70% of veterinarians for treating respiratory and neurological cases and by 40–50% when treating gastrointestinal and dermatological cases. Workplace conditions need improvement as 34.8% of workplaces did not have isolation units for infected animals, 21.1% did not have separate eating areas for staff, and 57.1% did not have complete PPE kits for use. Veterinarians were more likely to use PPE if they had undertaken postgraduate education, perceived that zoonosis exposure from animals and procedures was likely, consciously considered PPE use for every case they dealt with and believed that liability issues and risks encouraged use of PPE. In contrast, those working in private practices, those who tended to ‘just hope for the best’ when trying to avoid zoonotic diseases, and those who were not aware of industry guidelines were less likely to use PPE. The results suggest that veterinarians’ perceptions and workplace policies and culture substantially influence their use of PPE. Efforts should be made to encourage veterinarians and their workplaces to use infection control practices to protect themselves and their staff from zoonotic diseases

Factors affecting reproductive performance of dairy cows in a pasture-based, automatic milking system research farm: a retrospective, single-cohort study

A retrospective single cohort study was conducted to identify production and health factors associated with reproductive performance in a pasture-based automatic milking system research farm. The calving system of this herd shifted from split calving to year round calving gradually during the study period. Data from 365 cows with 798 lactations were analysed in the study. Reproductive outcome variables of interest were intervals from calving to first oestrus, to first insemination, and to conception as well as number of inseminations per conception, probability of submission for insemination by 80 days in milk, probability of conception by 100 days in milk and probability of conception at first insemination. Production factors (milk yield and its composition; milking frequency), record of periparturient disease, parity and season of calving were considered as predictor variables. The associations between predictor and outcome variables were assessed by multivariable linear regression, logistic regression and survival analyses for quantitative, binary and time-to-event outcomes, respectively. Average milk yield and milking frequency during 100 days in milk were not significantly associated with any of the reproductive measures. The likelihood of conception by 100 days in milk decreased gradually with year of automatic milking systems commissioning. Cows calved in autumn were 43% (hazard ratio: 1.43, P < 0.05) more likely to conceive compared to cows that calved in summer. Multiparous cows were more likely (P < 0.05) to be recorded for oestrus compared to primiparous cows. Twinning was negatively associated with the reproductive outcomes measured in the automatic milking systems research herd. Milk yield and milking frequency during 100 days in milk had no effect on reproductive measures in the pasture-based automatic milking system research herd. Key words: Reproduction, Automatic Milking System, Pasture-Based Syste

Factors affecting reproductive performance of dairy cows in a pasture-based, automatic milking system research farm: a retrospective, single-cohort study

A retrospective single cohort study was conducted to identify production and health factors associated with reproductive performance in a pasture-based automatic milking system research farm. The calving system of this herd shifted from split calving to year round calving gradually during the study period. Data from 365 cows with 798 lactations were analysed in the study. Reproductive outcome variables of interest were intervals from calving to first oestrus, to first insemination, and to conception as well as number of inseminations per conception, probability of submission for insemination by 80 days in milk, probability of conception by 100 days in milk and probability of conception at first insemination. Production factors (milk yield and its composition; milking frequency), record of periparturient disease, parity and season of calving were considered as predictor variables. The associations between predictor and outcome variables were assessed by multivariable linear regression, logistic regression and survival analyses for quantitative, binary and time-to-event outcomes, respectively. Average milk yield and milking frequency during 100 days in milk were not significantly associated with any of the reproductive measures. The likelihood of conception by 100 days in milk decreased gradually with year of automatic milking systems commissioning. Cows calved in autumn were 43% (hazard ratio: 1.43, P < 0.05) more likely to conceive compared to cows that calved in summer. Multiparous cows were more likely (P < 0.05) to be recorded for oestrus compared to primiparous cows. Twinning was negatively associated with the reproductive outcomes measured in the automatic milking systems research herd. Milk yield and milking frequency during 100 days in milk had no effect on reproductive measures in the pasture-based automatic milking system research herd. Key words: Reproduction, Automatic Milking System, Pasture-Based Syste