Associate Editor positions at Physical Review Letters

Physical Review Letters seeks three dynamic and personable individuals with postdoctoral experience in quantum information science and technology, photonics, condensed matter physics, or materials science to join their close-knit team of editors running the world’s leading physics journal. No editorial experience is required, though familiarity with the review process as an author and referee is expected.

These are full-time positions. While the work can be done remotely, the successful applicants should be residing somewhere in the USA and responsive during East Coast working hours.

Further information on the application process may be found here!

Postdoctoral Position at Wave Transport in Complex Systems Lab—Wesleyan University

The Wave Transport in Complex Systems (WTICS) Lab at Wesleyan University is
opening a post-doctoral position on wave transport in theory or/and experiment
using microwave and RF analogue circuitry. The candidate must have a basic
knowledge of theory of metamaterials. A knowledge of software packages for
electronic design (such as COMSOL, SPICE etc) is desirable. Specific areas of research that are relevant to the current post include:

(a) Artificial Intelligence and Machine Learning;
(b) Non-Hermitian systems;
(c) Active topological structures;
(d) Asymmetric transport;
(e) Wavefront shaping techniques

The position is for two years with a possible extension of a third year. Information
about the WTICS group can be found here. Interested candidates should send a CV, a short statement of work and three recommendation letters to Prof. T. Kottos at tkottos@wesleyan.edu.

Observing strongly-coupled Mie polaritons using water droplets

Mie theory, the analytical solution for electromagnetic wave scattering off a spherical particle, provides a powerful approach for understanding scattering spectra in terms of different multipole resonances. While the assumption of spherical symmetry is often merely an approximation, Mie theory can nevertheless give useful insights in more realistic settings such as resonances of cylindrical high refractive index nanopillars.

One setting where spherical scatterers arise quite naturally is in liquids with high surface tension, which promotes the formation of spherical droplets. Remarkably, for the case of water droplets with radii of a few microns, the Mie resonances coincide with the infrared stretching and bending vibrational resonances of the H2O molecule! This leads to strong coupling between electromagnetic and vibrational degrees of freedom leading to the formation of polaritons, as reported in recent work published in Physical Review Letters: Self-Hybridized Vibrational-Mie Polaritons in Water Droplets.

Observing the key signature of strong coupling - Rabi splitting between upper and lower polariton resonances (corresponding to electromagnetic and vibrational oscillations being in or out of phase) - using water droplets is complicated by the non-uniform droplet sizes. Thus, the measured scattering spectrum involved not just a few resonances at specific frequencies, but a distribution of different resonance frequencies dependent on the particles' sizes.

To overcome this, the authors of the study also measured the scattering spectra of droplets of heavy water, where the vibrational modes become red-shifted due to the increased mass of the deuterium atoms. The authors observed that the absorption peaks associated with the strong coupling between vibrational and electromagnetic resonances are also red-shifted.

In addition to applications to the spectra of water droplets in the atmosphere, it will be interesting to explore similar strong coupling phenomena in other high surface tension liquids and applications to polariton chemistry, whereby strong coupling between electromagnetic and molecular degrees of freedom shows promise as a means of controlling rates of chemical reactions.

From NISQ to small logical quantum circuits

After six years of huge interest in NISQ (noisy intermediate-scale quantum) circuits there are still no practical applications where a noisy quantum device can outperform the best classical methods. Noise is too detrimental, and classical methods are too powerful. Experts continue to argue that now is not the time for commercial applications: quantum error correction, hundreds of logical qubits, and millions of error-corrected gates are needed.

Then what's next? Circuits of a moderate size with some limited error correction capabilities. LISQ (logical intermediate-scale quantum) or something else, for short.

What can we expect from these up and coming small scale logical circuits?

First, a lot of the tools developed for the NISQ era will become obsolete. For example, variational quantum circuits involving continuously-parameterised quantum gates cannot be easily implemented in a fault-tolerant manner. Instead, post-variational hybrid quantum-classical algorithms for this era will need to offload the continuously-parameterised part of the algorithm to a classical computer, with the quantum circuit used to measure a set of (hopefully classically-intractable) observables that are used as inputs to the classical tunable model.

Second, the hardware, algorithms, and the error correcting code cannot be considered in isolation. Choosing the right error correcting code will be essential to get the most out of the current hardware. Examples of this can be seen in QuEra's logical circuit demonstration from late last year, where the use of a 3D quantum error correction code allowed them to perform random IQP circuit sampling with error detection, and Quantinuum's recent demonstration of repeated error correction. Similar to the NISQ era, different hardware platforms will have different strengths and limitations in what kinds of circuits they will be able to run.

Finally, the most valuable software tools in the NISQ era were for quantum control and state tomography, essential to get the most out of the noisy hardware. These tools will remain important, since fidelities at the physical qubit level directly affect the amount of quantum error correction overhead required. As we move to logical circuits, the new valuable quantum software will be in the form of compilers that will take all the hassle out of hardware and error code selection out of the end-user and translate a given logical circuit into simple, understandable hardware requirements.

Bob Dewar (1944-2024): theoretical plasma physicist

I was sorry to hear last week that Bob Dewar passed away while on a sabbatical at Cambridge. There are some tributes on the ANU MSI website, where he was an Emeritus Professor and still remained active in research.

Bob was my supervisor for a summer research project I undertook in 2009, at the end of my second year of undergraduate studies. At this time I was still unsure whether I would do a theoretical or experimental project if embarking on a PhD, let alone what topic it would be in, and this was my first experience of a research project in theoretical physics.

On my first day, Bob handed me an ancient monograph - his MSc thesis from 1967! - and assigned me the problem of getting some old Fortran code from the appendix working on a modern system. The code was designed to efficiently evaluate the wake potential left by a charged particle moving through a plasma by making use of clever analytical tricks and special function identities. Code efficiency was vital in that era, when programs were written on punched cards and the whole university had to share time on a single computer! Nowadays with easy access to computer algebra systems we are lazier and the art of special functions and asymptotic expansions is less widely appreciated. It was a fun little project for the summer, capped off with the opportunity to present the work at the Gaseous Electronics Meeting, held near Bateman's Bay that year. Later we (well, mostly Bob) wrote a paper out of this project. Whenever I see the wake left by a boat or swimming duck I am reminded of this work.

Bob was an inspiring mentor, representative of a kinder, more humble era of science where there was the freedom to follow a passion and spend decades digging into a single area of expertise throughout one's career and into retirement.

Postdoctoral Positions at Nankai University, Tianjin, China

Applications are solicited for postdoctoral positions in experimental/theoretical optics and photonics in the research group of Prof. Zhigang Chen/Hrvoje Buljan at Nankai University, China, which is one hour away from the capital Beijing and the alma mater of Shiing-Shen Chern. The areas of emphasis are topological photonics, nonlinear optics, optical trapping and manipulation, and machine-learning photonics. A PhD in physics, optics, or related area is required. It is expected that the candidate should have basic numerical skills and/or optical experimental skills and research experience with a good track of record in publications.

The initial appointment will be for three years, with the possibility of extension pending on performance and research funding. If accepted, the salary is competitive (annual gross salary > RMB 500,000, about $70,000), with possible additional merit award depending on academic performance evaluated at the end of each year. Free on-campus apartment is available, and the living cost is very low compared to income. The position will be funded under the China Postdoctoral International Exchange and Introduction Program, with the purpose of attracting outstanding PhD graduates to join the university and conduct postdoctoral research.

Applicant eligibility:
1. In general, applicants shall be under the age of 35. As for key disciplines supported by the university, the limitation on age can be eased to 38 years old.
2. Both Chinese and foreign graduates obtaining their PhD (from overseas top universities or supervised by an internationally recognized scientist) in recent 3~5 years can apply.
3. PhD candidates who meet the above conditions can also apply if they can start the postdoctoral position by June 2025.

Interested candidates are encouraged to contact Professor Chen or Professor Buljan before April 20, 2024 for application this year. However, the starting date is flexible.

Website: https://topo-photonics.nankai.edu.cn/index.htm

Arxiv April Fools'

This year there are quite a few joke papers cross-listed in the popular physics category. My favourite: "Is Winter Coming?"

Particularly memorable entries from previous years include "Novel approach to Room Temperature Superconductivity problem" and "A solvable string theory in four dimensions."