Quantum noise reduction using a cavity with a Bose Einstein condensate

We study an optomechanical system in which the collective density excitations (Bogoliubov modes) of a Bose Einstein condensate (BEC) is coupled to a cavity field. We show that the optical force changes the frequency and the damping constant of the collective density excitations of the BEC. We further analyze the occurrence of normal mode splitting (NMS) due to mixing of the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction. The NMS is found to vanish for small values of the two-body interaction. We further show that the density excitations of the condensate can be used to squeeze the output quantum fluctuations of the light beam. This system may serve as an optomechanical control of quantum fluctuations using a Bose Einstein condensate.Comment: 8 figure

Mathematical framework for simulations of quantum fields in complex interferometers using the two-photon formalism

We present a mathematical framework for simulation of optical fields in complex gravitational-wave interferometers. The simulation framework uses the two-photon formalism for optical fields and includes radiation pressure effects, an important addition required for simulating signal and noise fields in next-generation interferometers with high circulating power. We present a comparison of results from the simulation with analytical calculation and show that accurate agreement is achieved

Thermal noise in microfabricated AlGaAs structures

Multilayer crystalline AlGaAs stacks have the potential to reduce coating thermal noise in future gravitational-wave interferometers. The results of direct measurements of thermal noise in microfabricated AlGaAs structures will be presented

An all-optical trap for a gram-scale mirror

We report on a stable optical trap suitable for a macroscopic mirror, wherein the dynamics of the mirror are fully dominated by radiation pressure. The technique employs two frequency-offset laser fields to simultaneously create a stiff optical restoring force and a viscous optical damping force. We show how these forces may be used to optically trap a free mass without introducing thermal noise; and we demonstrate the technique experimentally with a 1 gram mirror. The observed optical spring has an inferred Young's modulus of 1.2 TPa, 20% stiffer than diamond. The trap is intrinsically cold and reaches an effective temperature of 0.8 K, limited by technical noise in our apparatus.Comment: Major revision. Replacement is version that appears in Phy. Rev. Lett. 98, 150802 (2007

Achieving ground state and enhancing entanglement by recovering information

For cavity-assisted optomechanical cooling experiments, it has been shown in the literature that the cavity bandwidth needs to be smaller than the mechanical frequency in order to achieve the quantum ground state of the mechanical oscillator, which is the so-called resolved-sideband or good-cavity limit. We provide a new but physically equivalent insight into the origin of such a limit: that is information loss due to a finite cavity bandwidth. With an optimal feedback control to recover those information, we can surpass the resolved-sideband limit and achieve the quantum ground state. Interestingly, recovering those information can also significantly enhance the optomechanical entanglement. Especially when the environmental temperature is high, the entanglement will either exist or vanish critically depending on whether information is recovered or not, which is a vivid example of a quantum eraser.Comment: 9 figures, 18 page

Design of microresonators to minimize thermal noise below the standard quantum limit

Microfabricated resonators play a crucial role in the development of quantum measurement, including future gravitational wave detectors. We use a micro-genetic algorithm and a finite element method to design a microresonator whose geometry is optimized to maximize the sub-Standard Quantum Limit (SQL) performance including lower thermal noise (TN) below the SQL, a broader sub-SQL region, and a sub-SQL region at lower frequencies. For the proposed design, we study the effects of different geometries of the mirror pad and cantilever microresonator on sub-SQL performance. We find that the maximum ratio of SQL to TN is increased, its frequency is decreased, and the sub-SQL range is increased by increasing the length of the microresonator cantilever, increasing the radius of the mirror pad, decreasing the width of the microresonator cantilever, and shifting the laser beam location from the mirror center. We also find that there exists a trade-off between the maximum ratio of SQL to TN and the sub-SQL bandwidth. The performance of this designed microresonator will allow it to serve as a test-bed for quantum non-demolition measurements and to open new regimes of precision measurement that are relevant for many practical sensing applications, including advanced gravitational wave detectors

Squeezing in the audio gravitational wave detection band

We demonstrate the generation of broad-band continuous-wave optical squeezing down to 200Hz using a below threshold optical parametric oscillator (OPO). The squeezed state phase was controlled using a noise locking technique. We show that low frequency noise sources, such as seed noise, pump noise and detuning fluctuations, present in optical parametric amplifiers have negligible effect on squeezing produced by a below threshold OPO. This low frequency squeezing is ideal for improving the sensitivity of audio frequency measuring devices such as gravitational wave detectors.Comment: 5 pages, 6 figure

Instagram as a Tool of Diffusion for the Livestock Industry

Studies have shown that more people are getting their information through social media (SM). With so much misinformation presented in global media, it is difficult for consumers to distinguish what is true and what isn’t. With negative images and minimal context, consumers have a tendency to believe and trust what they see on SM. After IRB approval, a survey study was launched on Qualtrics and accessed via email. Using Instagram as platform, this study presented 5 cognitively and 5 emotionally oriented posts focused on the aspects of animal welfare, diet/health, and environment/sustainability. Prior to viewing the Instagram posts, study participants were given a 5-scale Likert pre survey assessing their opinions about their views of animal welfare, diet/health of consumers of red meat and environment/sustainability for the beef industry. Participants subsequently viewed the posts and then took a post survey. SPSS was used to analyze responses with t-tests and frequencies. ATLAS was used to code for negative and positive key words in open responses. Results showed that participant’s views about the beef industry improved (p \u3c .05) after viewing the media posts for welfare and that participants favored the suggestions that beef cattle are treated humanely. Participants were unsure of the effects that beef consumption has on consumers’ diet and health as well as the environment. Qualitative results suggest that viewing of the posts had a favorable impact on consumer’s opinions

Sustainability strategy and blockchain-enabled life cycle assessment: a focus on materials industry

Sustainable development, especially with the 2030 Agenda for Sustainable Development and its Sustainable Development Goals (SDGs), has been a priority of corporations. Nevertheless, processes which are required to deliver both changes and impact to create a sustainable organization have been slow and challenging. The purpose of this research is first to explore the extent and nature of eco-sustainability policy and strategy implementation of Materials Industry Group (MIG) companies listed on the Australian Securities Exchange (ASX). The analysis shows that strategy is the core element for organizational sustainable development and strategy needs to be implemented at the enterprise-wide level and aligned with other dimensions within the McKinsey Seven S’s (7S’s) framework. The capabilities of life cycle assessment (LCA) that provides a holistic assessment of environmental impacts of products, from upstream and downstream perspectives, is under-explored. The case companies used in this research find it challenging to implement LCA. This research adds an additional dimension to the existing framework, suggesting the possibilities of adopting blockchain technology in strategizing sustainability strategy. Blockchain in the systems of the framework can be used in LCA to support sustainability and help organizations to achieve their targeted SDGs