A-CUHK403/15
Quantum Information Processing with Spin Ensembles

Hong Kong Principal Investigator: Prof Liu Renbao (The Chinese University of Hong Kong)
Mainland Principal Investigator: Dr Bertet Patrice (CEA Saclay)

Quantum computing can revolutionize the information technology. Practical quantum computing requires precise initialization, storage, control, readout, and transfer of quantum states. Various candidate systems have promising features on some aspects; however, none of them meets all the requirements. A new trend in the research of this field is to hybridize different types of systems and to combine their advantages. A particularly promising hybrid quantum system is superconducting quantum devices coupled to many electron spins in solids, called spin ensembles. The superconducting devices have the advantages of easy control, initialization, readout, and remote transfer of quantum states but have relatively short quantum coherence time. Electron spins in solids (e.g., nitrogen-vacancy centers in diamond and bismuth donors in silicon) have long coherence times. Spin ensembles have thus been proposed as quantum memories for superconducting qubits.

This joint project will form a strong-strong union of an experimental team in France and a theoretical team in Hong Kong to solve the key physics problems in superconductor-spin hybrid systems for quantum computing. We will team up to design, construct, and optimize hybrid superconductor-spin systems, with the goal of demonstrating the first operational quantum memory for superconducting qubits. We will study decoherence of collective modes in spin ensembles and implement quantum control to preserve coherence of collective spin states for multi-mode quantum memory.

This project is expected to lay the foundation of quantum computing using the superconductor-spin hybrid systems. It will also help consolidate the cultural and educational connections between France and Hong Kong.

A-PolyU503/15
Experimental and Numerical Studies of Innovative Acoustical Material Technology for Industrial and Urban Low-Frequency Noise Mitigation

Hong Kong Principal Investigator: Dr Leung Randolph Chi-kin (The Hong Kong Polytechnic University)
Mainland Principal Investigator: Prof Aurégan Yves (Université du Maine)

Airflows are frequently employed to transfer heat and mechanical work in many technical processes in transportation vehicles and industrial/building utilities, including ventilation and air-conditioning (VAC) systems in vehicles and buildings, cooling systems in laptops and engines, IC-engines, power-plants, household appliances, etc. Notwithstanding the advances in noise control technology in last two decades, the low-frequency noise produced by airflow systems is still the major contributor to bad acoustic environment in our homes/offices and community-wise noise annoyance in cities.

Modern low-fuel-consumption aircraft engine designs inevitably induce larger fan diameter with less blades, slower rotation, and shorter/thinner nacelles. The fan noise then dominates around 500-Hz which is effectively transparent to conventional acoustic liners. New acoustic absorber concepts for fan noise are urgently needed as the air-traffic growth is accelerating worldwide. For land transportation, the noisy flows from engine-cooling, exhaust flow and VAC systems are largely responsible for the street-level environmental annoyance and cabin discomfort. Nowadays, the vehicle acoustic comfort is a critical attribute that determines customers' satisfaction worldwide. The transportation industry is heavily challenged by the community-push for ecology-oriented designs which usually leads to lighter but noisier vehicles. These conflicting requirements seriously hinder the eco-design push, especially in the high-end markets where the customers are reluctant to lower their comfort expectation.

In highly-urbanized cities filled with high-rise buildings, low-frequency noisy flows in the extensive VAC systems, and created by household appliances are primary sources for indoor acoustic nuisance. Bulky conventional dissipative silencers are widely installed to attenuate the VAC flow noise but its installation inevitably increases the system flow pressure loss which lowers the system energy efficiency significantly. In Hong Kong where the VAC systems consume more than 90% of electricity, it simply transforms the noise problem into a more serious energy wastage problem. That makes the city less sustainable. The use of porous silencers is prohibited in areas under stringent hygiene control (e.g. hospitals) and when the air is dirty and/or greasy. Although the aforementioned noise problems are expected worsening in coming decade, research on new concepts that support better solutions is still lacking. This project studies novel acoustical material technologies for mitigating low-frequency airflow noise through a systematic in-depth study of the inherent sound-flow-material interactions. The project outcomes are expected to provide established technology/design options to transportation and building industries for achieving better living quality yet maintaining the sustainability of the environment.

A-HKIEd801/15
The role of consonants, vowels and tones in early lexical acquisition (COVOTO)

Hong Kong Principal Investigator: Prof Cheung Hin Tat (The Education University of Hong Kong)
Mainland Principal Investigator: Dr Nazzi Thierry (Laboratoire psychologie de la Perception CNRS)

Research in infant speech perception has demonstrated that infants are endowed with rich speech capacities that allow them to discriminate many consonantal and vocalic contrasts and to become attuned to the language-specific properties of their native language quickly. An asymmetry insensitivity between consonants and vowels in word learning is first reported in French-learning infants, to the advantage of consonants (C-bias) but subsequent studies revealed that infants exposed to English and Danish displayed no bias or higher sensitivity to vowels. The C-bias, though possibly very stable in adulthood, might not follow the same trajectory cross-linguistically in infancy, pointing towards complex interactions between infants' endowed speech capacity and their linguistic experience. So far, studies have been limited in two ways: (a) to European languages, and (b) to consonants and vowels, therefore ignoring one crucial linguistic dimension: tonal information. This is a serious limitation given that the majority of languages in the world use tone contrasts at the lexical level. Accordingly, the present project will be the first to address this issue, exploring infants' relative sensitivity to and use of consonants, vowels and tones in Cantonese and French environments. Data from French and Cantonese toddlers between 14 to 30 months will be collected in two sites: Paris and Hong Kong. Eyetracking experimental tasks will be designed for investigating these toddlers' use of consonant, vowel and tone contrasts in learning new words, and how non-relevant tone variation may interfere with the word acquisition process, with parallel experimental design and stimulus in both sites. Monolingual French-learning infants will also be examined by a training study for exploring the role of linguistic training in the perceptual reorganization of tone information. Experimental tasks will be further extended to bilingual toddlers. By comparing results from these tasks, the role of linguistic input, its interaction with the innate perceptual capacity for lexical acquisition and its course of development will then be systematically investigated.