Quantum Matter 'On-a-Chip' II

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The mid and long-term goal of our team at McGill is to elucidate new quantum phases of matter `on-a-chip' engineered in semiconductor electronic and fluidic structures. By 'quantum matter', I mean phases of matter whose behaviour is dictated by quantum rules rather than the more conventional newtonian physics that surrounds us. By `on-a-chip', I mean on a platform similar to the processors found in modern computers. Material-wise, we use extremely low-disorder GaAs/AlGaAs grown in the highest mobility (i.e. cleanest) Molecular Beam Epitaxy (MBE) facility in the World (Princeton), as well as the cleanest material in Nature, 3He near absolute zero. Starting from raw semiconducting materials, we tailor-fabricate structures for electrons, or nanoholes for quantum fluids, using cutting-edge clean room fabrication processes evolved from the nanotech community. When the existing tools simply do not exist, we develop them and at times we file them for IP protection (patent) with McGill so as to promote the tech transfer. Below are the experiments we propose to pursue under the tenure of this grant:**1) Thermodynamic Signature of a Non-abelian Quantum Phase*In elementary quantum physics textbooks, we learn that all (identical) quantum particles can be classified into two categories, according to their properties upon exchange. These two types of particles are fermions (such as electrons, protons, etc) and bosons (photons, 4He, etc). While correct in three dimensions, this need not to be true in two-dimensions where quantum statistics may exist that differ from the boson and fermion case. This project intends to demonstrate the existence of such non-abelian quantum phases by way of thermodynamic measurements 'on-a-chip'.**2) Coulomb drag and Tomonaga-Luttinger Liquid in Quantum Wires*In quantum physics, one-dimensional correlated states can be modeled via a theory with exact solutions known as the Tomonaga-Luttinger liquid model. Despite its mathematical elegance, little is known experimentally regarding the behaviour of one-dimensional quantum systems. We have recently been able to fabricate quantum wires coupled in the vertical geometry by less than 15 nm, a World first. This projects thus intends to unravel the Luttinger physics that is predicted to occur in clean quantum wires by way of Coulomb drag measurements. **3) A Quantum Faucet: Quantized Mass Flow at the Nanoscale*A clean quantum wire has its conductance quantuzed in units of 2e^/h, i.e. it depends only on the fundamental constants e and h. The question I am posing here is: could similar physics be observed in the mass flow of a real fluid system where the pressure gradient, the analogue to a voltage drop in a device, drives the flow (as in a faucet)? This project aims to experimentally demonstrate that at the nanoscale, for a quantum system, the conductance for the pipe should be quantized in unit of G_m=2m^2/h, the fundamental quantum of mass flow. **4) 'Sonic' Black Hole and the Unruh Effect*Black holes are ubiquitous in the Universe, and despite their great interest, the celebrated 'black hole evaporation' predicted by Hawking in 1974 was never confirmed by observation. In 1981, Canadian physicist Unruh showed that the Euler equation describing the flow of an inviscid fluid supports a metric that has the same mathematical structure as the Schwarzschild metric for the black hole horizon. Using similar arguments used by Hawking, Unruh predicted 'Hawking radiation' of a sonic black hole for high-speed fluid flow. This project intends to study the 'conjectured' acoustic horizon predicted to occur in transsonic fluid flow, and explore experimentally the analogy between black hole physics and fluid dynamics.