Category Archives: General

Marsden grant!

Photons on demand: dial up your number

Our group has been awarded a Marsden grant starting in 2022, totalling $921k over three years. Summary:

Optical quantum technologies are poised to revolutionise communication, computing, and metrology. Access to light sources that deterministically provide a precisely known number of photons (light quanta), or more generally light of a prescribed, uniquely quantum mechanical nature, is key to unlocking the full potential of these technologies. We will build such a source that consists of a single atom trapped near the surface of a piece of optical fibre that has been tapered to a width of just a few hundred nanometres, less than one per cent of the thickness of a human hair. The source works by using the quantum mechanical properties of absorption and emission of light by an atom and utilises the nanometre-size fibre to efficiently capture the quantum light emitted by the atom and then guide this light into regular telecommunication fibre. This light source will be truly quantum in nature and will yield large benefits to the quantum technology industry.

Bose(-Einstein) Condensate paper published

Since the realisation by Bose and Einstein in 1924 that the quantum ground state of a system is special in many ways, researchers have worked towards creating a quantum system with many particles occupying that ground state, now called a Bose-Einstein Condensate (BEC), with the first successful demonstration in 1995.

Here, we argue that BECs can be formed in non-ground states as we recently demonstrated and that the laboratory ground state does not have zero kinetic energy, as asserted by Einstein in 1925. We show that some naïve transformations in the literature have mistakenly supported the zero-kinetic energy ground state argument.

With this paper, we clarify the necessary conditions for a Bose condensate and pave the way for future experiments with non-ground state condensates.

The paper can be found here:

“A Bose-Einstein condensate is a Bose condensate in the laboratory ground state” published online and to appear in the October print issue with Proceedings of the Royal Society A. 477, p.20210465 doi: 10.1098/rspa.2021.0465

Breakthrough paper published!

We have determined the energy difference between two quantum states in the helium atom with unprecedented accuracy, a ground-breaking discovery that contributes to our understanding of the universe and space-time and rivals the work of the world’s most expensive physics project, the Large Hadron Collider.

Our understanding of the universe and the forces that govern it relies on the Standard Model of particle physics. This Model helps us understand space-time and the fundamental forces that hold everything in the universe in place. It is the most accurate scientific theory known to humankind.

But scientists know the Standard Model does not fully explain everything, for example, it doesn’t explain gravity, dark matter, dark energy, or the fact that there is way more matter than antimatter in the universe.

So scientists are continually testing the Model by manipulating and controlling matter at the atomic level, looking for effects that cannot be explained directly – in this case the helium atom, which is the second most simple atom after hydrogen.

The latest experiment carried out by Dr Maarten Hoogerland from the University of Auckland and the Dodd-Walls Centre for Photonic and Quantum Technologies and Dr Wim Vassen from Vrije University in the Netherlands, was to test the helium atom’s transition between two states of energy. This is sometimes referred to as a quantum jump, or leap.

The significant change in energy in the atom is then precisely measured to estimate the diameter of the nucleus. This is done in an experiment that could fit on a tabletop with ultra-cold gas using an ultra-stable laser, accurate to a million times a million or, if you were using this level of measurement to measure the distance from Earth to the moon, it would be accurate to within a fraction of a millimetre.

“The fact the transition occurred is rare, and a milestone for quantum physics research. It advances our knowledge of the way atoms are put together and hence contributes to our understanding of space-time,” Dr Hoogerland says

“This new result is a great test for our understanding of the Model and also allows us to determine the size of the helium nucleus and of the helium atom. This has been the subject of intensive research for decades so for our experiment to have succeeded is an incredibly exciting result.”

The Large Hadron Collider is the largest machine ever built and a major international project involving hundreds of scientists looking for effects that cannot be explained by the Standard Model directly and for new particles at very high energy that do not fit the  Model.

The research is published here:

A great summary appeared in the New Zealand Herald

Also we appeared on the radio this morning!

More news coverage on the business scoop

Again in Photonics Online!