To make a nanomechanical Schr\"{o}dinger-cat mew

By an explicite calculation of Michelson interferometric output intensities in the optomechanical scheme proposed by Marshall et al. (2003), an oscillatory factor is obtained that may go down to zero just at the time a visibility revival ought to be observed. Including a properly tuned phase shifter offers a simple amendment to the situation. By using a Pockels phase shifter with fast time-dependent modulation in one arm, one may obtain further possibilities to enrich the quantum state preparation and reconstruction abilities of the original scheme, thereby improving the chances to reliably detect genuine quantum behaviour of a nanomechanical oscillator.Comment: For Proc. DICE-2010 (Castiglioncello), to be published in J. Phys. Conf. Ser., 201

Use of Oral Sodium Phosphate Colonic Lavage Solution by Canadian Colonoscopists: Pitfalls and Complications

Oral sodium phosphate (NaP) has become an attractive alternative to polyethylene glycol (PEG) for colonic cleansing before colonoscopy, but it potentially has greater complications. This study surveyed members of the Canadian Association of Gastroenterology (CAG) to determine how these colonic lavage agents are used and what complications have been encountered. The Dillman survey technique produced responses from 67% of the 400 members who perform colonoscopy. For the larger out-patient group, respondents used NaP more frequently than PEG (46% versus 35%, respectively, P<0.015). Respondents used NaP and PEG with similar frequencies for the in-patient group (44% versus 43%). Of respondents using NaP, 45% reported excluding its use in patients with renal failure, 30% with heart disease, 13% with incomplete bowel obstruction and 9% with extreme age. Symptoms suggestive of hypovolemia were reported in 9% of those using NaP compared with 3% using PEG (P<0.02). Three patients receiving NaP developed acute renal failure. A greater proportion of those using NaP had small unexplained aphthous ulcers (16%) and excessive luminal bubbling (24%) compared with PEG users (3%, P<0.00001 and 14%, P<0.03, respectively). These data demonstrate that members of CAG use NaP more frequently than PEG as the colonic lavage solution before colonoscopy. A greater number reported complications with NaP versus PEG, and a significant proportion of the respondents appeared to be unaware of the potential for these complications in specific clinical circumstances

Quantum and Classical Phases in Optomechanics

The control of quantum systems requires the ability to change and read-out the phase of a system. The non-commutativity of canonical conjugate operators can induce phases on quantum systems, which can be employed for implementing phase gates and for precision measurements. Here we study the phase acquired by a radiation field after its radiation pressure interaction with a mechanical oscillator, and compare the classical and quantum contributions. The classical description can reproduce the nonlinearity induced by the mechanical oscillator and the loss of correlations between mechanics and optical field at certain interaction times. Such features alone are therefore insufficient for probing the quantum nature of the interaction. Our results thus isolate genuine quantum contributions of the optomechanical interaction that could be probed in current experiments.Comment: 10 pages, 3 figure

Non-linear optomechanical measurement of mechanical motion

Precision measurement of non-linear observables is an important goal in all facets of quantum optics. This allows measurement-based non-classical state preparation, which has been applied to great success in various physical systems, and provides a route for quantum information processing with otherwise linear interactions. In cavity optomechanics much progress has been made using linear interactions and measurement, but observation of non-linear mechanical degrees-of-freedom remains outstanding. Here we report the observation of displacement-squared thermal motion of a micro-mechanical resonator by exploiting the intrinsic non-linearity of the radiation pressure interaction. Using this measurement we generate bimodal mechanical states of motion with separations and feature sizes well below 100~pm. Future improvements to this approach will allow the preparation of quantum superposition states, which can be used to experimentally explore collapse models of the wavefunction and the potential for mechanical-resonator-based quantum information and metrology applications.Comment: 8 pages, 4 figures, extensive supplementary material available with published versio

Researchers Experience Multiple Embodiments in a Cross-Cultural, Intergenerational Event to Support Girls Challenging Gender-Based Violence

Many challenges exist to conducting participatory research and consultation with young people, especially with those considered vulnerable or at risk. Beyond respecting the safety and wellbeing of young research participants, researchers must be aware of barriers to youth engagement and be attuned to the many forms of youth resistance. As young people are seeking more control over their lives, traditional knowledge hierarchies between adults and youth are shifting. In July 2018, an event entitled Circles Within Circles brought together Indigenous and non-Indigenous girls and young women from South Africa, Canada, Russia, Sweden, and Kenya to learn from each other’s participatory art-making and create a network for challenging gender-based violence (GBV). This article provides insight into the often-invisible experience of the “supporting cast” in events like Circles Within Circles. The co-authors are doctoral and postdoctoral researchers who contributed to organization and acted as facilitators, notetakers, and participants. The co-authors conduct participatory analyses of journal entries they wrote throughout the event, and jointly reflect on the activities and their feelings about their roles. Reflecting, for example, on gut feelings about young participants’ use of voice and silence during adult-led activities, the co-authors discuss their reading of girls’ demonstrations of resistance. This embodied knowledge, further cultivated by attuning to shared experience, is explored in this collaborative auto-ethnography. Examining the complexities of this cross-cultural and intergenerational event, the co-authors contend that when supporting girls and young people subverting dominant narratives of GBV, researchers’ embodied reflexivity is crucial for positively contributing to girl-led change

Mechanical squeezing via fast continuous measurement

We revisit quantum state preparation of an oscillator by continuous linear position measurement. Quite general analytical expressions are derived for the conditioned state of the oscillator. Remarkably, we predict that quantum squeezing is possible outside of both the backaction dominated and quantum coherent oscillation regimes, relaxing experimental requirements even compared to ground-state cooling. This provides a new way to generate non-classical states of macroscopic mechanical oscillators, and opens the door to quantum sensing and tests of quantum macroscopicity at room temperature