Tenure-Track Assistant Professor Opening at Singapore University of Technology and Design

My department is looking for a new tenure track faculty member with expertise in high performance computing applied to many-body quantum systems! Here is the job posting. Interested potential candidates are welcome to contact me with any questions about working at SUTD or the application process.

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The Singapore University of Technology and Design (SUTD) is a young and growing university with a unique structure and mission in the vibrant nation of Singapore. SUTD features a focus on design from an engineering and technological perspective, an intimate student to faculty ratio, an innovative active-based learning pedagogy, an interdisciplinary pillar organization, a stellar faculty, and a beautiful new campus. SUTD was established in 2009, in collaboration with MIT and Zhejiang University, as the fourth publicly funded university in Singapore. SUTD is also considered by international experts as an emerging leader in engineering education:  http://news.mit.edu/2018/reimagining-and-rethinking-engineering-education-0327

 

The Science, Mathematics and Technology (SMT) cluster has an open position to hire a tenure-track Assistant Professor with a strong record of scholarly research in high performance computing applied to many-body quantum systems such as condensed matter, quantum chemistry, quantum simulation or others. We are particularly interested in candidates with a background in tensor networks and/or neural quantum states. Postdoctoral experience is desired. We seek candidates with an open mind towards multidisciplinary research and whose research area, methods and/or tools can impact multiple fields and society. We can consider more senior candidates too, e.g. Assoc. Prof. and Prof.

 

The candidate will join a young and growing department including other experts in many-body quantum systems working in areas such as quantum simulation and quantum computation, quantum error correction, quantum-inspired computing, quantum open systems, quantum transport, quantum thermodynamics, photonics etc. Furthermore, Singapore offers a stimulating and well-funded research environment with many experts in town.

 

Candidates must be committed to excellence in teaching at the undergraduate and graduate levels and to developing and maintaining an active research program. Candidates should be able to teach undergraduate courses in mathematics, physics or chemistry. We are particularly interested in individuals with a strong and genuine interest in promoting STEM education at all levels. The successful candidate can look forward to internationally competitive remuneration, attractive research startup packages and grant opportunities, and assistance for relocation to Singapore.

 

Additional information about the university and the SMT cluster and SUTD can be found at www.sutd.edu.sg and https://smt.sutd.edu.sg/.

 

Application Requirements

 

Applications will be accepted online at https://careers.sutd.edu.sg/ and the review of applications will close on 4 January 2026.

 

Candidates should submit their full application packages, which should include:
 
•    Complete resume with full publication list (Including Statement of interest / Cover letter)
•    Research statement/plans
•    Teaching statement/plans
•    3 Research papers
•    Contact information of 3 referees

Double-bracket quantum algorithms

Recently Marek Gluza visited SUTD to give a seminar on double-bracket quantum algorithms. This is an interesting family of quantum optimization algorithms based on Riemannian geometry, which diagonalize an operator (or minimize an energy) using gradient descent in the space of unitary operators. For example, minimization of energy via this gradient descent is realized as the flow,

$$ \partial_t \rho = [ [\rho (t), H], \rho(t) ], $$

where the first commutator $[\rho(t), H]$ is the energy gradient in the space of unitary operators - the direction that locally minimises the energy of the state $\rho(t)$ - and the second commutator evolves $\rho(t)$ in this direction. In other words, this is a nonlinear evolution governed by the effective time-dependent Hamiltonian $H_{\mathrm{eff}} = [\rho(t),H]$. Similar flows were introduced by R. W. Brockett in the 1990s as a way to use dynamical systems to diagonalize matrices. When implemented with a finite step size $s$, this flow recursively generates better approximations to the ground state as

$$ \rho_{k+1} =  e^{s [\rho, H]} \rho_k.$$

Because of the recursion (you need to first generate $\rho_k$ before applying the next set of gates to make $\rho_{k+1}$), the circuit depth grows exponentially with the number of steps. On the other hand, in contrast to variational quantum algorithms (where one has to measure gradients of all the classical control parameters of the circuit), to implement the double-bracket flow you only need specify the initial state $\rho_0$ and the step size $s$, avoiding big problems such as barren plateaux and choosing an appropriate variational ansatz. Double-bracket flow is guaranteed to converge, so it can pick up after other methods get stuck.

Marek noted that because of the circuit depth blow up, a warm start is essential to get the best performance. For example, one might optimize a shallow variational quantum circuit such as QAOA to obtain a low energy state, followed by a few steps of double-bracket flow to home in on the ground state.

This is a great example of how quantum computing can draw inspiration from classical algorithms and control theory, giving a fresh application of the humble idea of optimization via gradient descent! 

The slides are available here.

Topological Photonics: Limitations and Possibilities

Last week our Perspective article "Limitations and possibilities of topological photonics" was published in Nature Reviews Physics. As the title suggests, we address some overblown claims of topological robustness frequently made in the literature and clarify in which areas topological protection can play a useful role for applications in photonics.

We first thought of writing such an article in July 2023, in response to several papers somehow being published in high impact journals despite their central claims being based on a misunderstanding of the nature of topological protection and robustness in the systems they studied. For example, claims of "topologically enhanced" or "topologically protected" localization are generally unfounded, given that the localization length is generally determined by the width of the band gap, a non-topological quantity.

Another common problem we wanted to address was the frequent use of comparisons between trivial and non-trivial structures to claim various forms of topological "enhancement". Sadly, such claims also frequently appear in top journals. As we discuss in the article, such a comparison ends up being meaningless because trivial and non-trivial structures host modes with differing dimensionality. For example, in 2D structures the edge modes (localized along the 1D boundary of the system) will naturally give a stronger light localization than a trivial 2D structure without any edge states. However, there are many ways to create edge states that do not require complicated topologically non-trivial designs. What matters is whether unidirectional chiral edge states (which are unique to topologically non-trivial systems) offer some advantage compared to non-chiral states, appearing either as trivial edge states or, more simply, as bulk states of a one-dimensional system. This kind of fair comparison is surprisingly rare in the literature - the most prominent example I know of is the 2014 paper "Topologically Robust Transport of Photons in a Synthetic Gauge Field". 

Unfortunately, this methodology was not widely adopted, and there was little progress on the hard problem of demonstrating quantitative performance enhancements of topological designs compared to state-of-the-art non-topological designs; for example, we had to wait until 2023 to see a rigorous comparison between scattering in valley Hall and non-topological photonic crystal waveguides. In this work, the non-topological W1 photonic crystal waveguide had lower scattering losses in the slow light regime.

Promoters of topological photonics may argue that such a comparison is also unfair, given that the W1 photonic crystal waveguide design is the result of years of testing, experimentation, and optimization, whereas the valley Hall design is much newer, with the potential for further optimization. This point brings me to the "possibilities" of topological photonics we discuss in our article: a topologically non-trivial band structure should not be the end of the design process. Rather, topological bands provide a unique starting point for further optimization, for example by guaranteeing the creation of localized modes near the middle of a band gap. Before the advent of topological band theory we did not have a systematic way to do this!

In the next phase of research in topological photonics, the focus will not be on demonstrating ever more exotic topological phenomena in increasingly more complicated setups. Rather, we should be aiming to integrate this new design tool with other approaches such as fine-tuning or inverse design to move from proofs of concept to genuinely better devices. Photonic crystal waveguides and fibers, integrated lasers, and frequency combs are three areas ripe for further breakthroughs, in my opinion. Watch this space for more on these topics!

GenQ Hackathon: Quantum for Finance

Last weekend I had the pleasure to attend the GenQ Hackathon: Quantum for Finance, joining as a mentor for the teams. Events such as this are important as a means of building familiarity with quantum processors amongst the participants from diverse backgrounds, from physics to finance majors and from high school students to veteran software engineers. Applications of quantum processors will not just need PhD-level quantum algorithm specialists, but also people with a broader range of skills able to make sense of where quantum algorithms may be practically useful.

The overall winning team had the, in my opinion, crucial insight that whatever fancy new solution you come up with, be it AI or quantum-designed, it had better be interpretable. Particularly in the high-stakes world of finance, someone will ultimately be responsible for decisions made based on the quantitative model. End-users won't trust a black box model. A model that spits out a single number - such as an F-score or correlation coefficient - will never be as trustworthy as a model that can clearly show all the relevant variables. Because of this, the team incorporated Mapper into their solution for detecting anomalies in the form of fraudulent credit card transactions.

One thing I was surprised by was how few of the teams took into account the clear advice given in the opening statement from Hongbin Liu (from Microsoft Quantum): In future practical use-cases of quantum processors, the cross-over point at which a quantum processor is expected to out-perform existing (very powerful) classical algorithms and high performance computers will involve days to weeks of wall-clock runtime. One on the judging criteria specifically focused on the scalability of the proposed solution. Despite this, in their final pitches many of the (unsuccessful) teams focused on quantum circuits limited to several qubits with second-scale run-times, claiming apparent speedups compared to selected classical benchmarks. However, such small-scale quantum circuits are trivially classically simulable.

I observed almost all the teams using ChatGPT or some other favourite large language model, both for background research on the chosen problem as well as rapid code generation. It was also striking to see how much easier it is now to write, compile, and execute quantum circuits on a cloud quantum processor by making use of quantum middleware providers, who now sell this as a convenient service. 

 

Cusp solitons mediated by a topological nonlinearity

Harvey just finished what should be the last paper of his PhD studies: Cusp solitons mediated by a topological nonlinearity

Harvey's PhD project studied the intersection between topological data analysis (TDA) techniques and nonlinear and many-body quantum dynamics. His first paper devised a TDA-based pipeline for detecting the emergence of quantum chaos in a periodically-driven nonlinear Kerr cavity. He followed this up with a demonstration of many-body quantum scar detection using topology-based dimensional reduction.

These works, while very nice, were ultimately using TDA to recover known physics. We really want to find examples where TDA can unveil new physics. This is a hard problem. Where to look? And what counts as "new"?

The easier solution for us was to insert TDA "by hand" into a nonlinear model, and see what came out of it.

For our testbed we took the nonlinear Schrodinger equation, frequently used to model nonlinear waves in various platforms. In the usual nonlinear Schrodinger equation, the conserved energy is the Hamiltonian,

$$ H = \int dx \left[ \frac{1}{2} |\partial_x \psi |^2 - \frac{g}{2} |\psi|^4 \right] $$

The second term, responsible for the nonlinear dynamics, can be interpreted as an intensity-dependent potential of depth $\frac{g}{2}|\psi|^2$. We looked at what would happen if we replaced this term with a quantity obtained using TDA. When dealing with one-dimensional functions, such as intensity profiles $|\psi(x)|^2$, TDA frequently uses sublevel set persistent homology, characterizing shape in terms of the persistence of local maxima and minima. We used the total persistence of these features as an energy penalty term, leading to

$$ H^{\prime} = \int dx \left[ \frac{1}{2} |\partial_x \psi|^2 - \alpha \mathrm{sgn}( \partial_x |\psi|^2 ) (\partial_x |\psi|^2) \right]  $$

Deriving the equations of motion, we found that this topological energy penalty gives rise to effective $\delta$ function potentials at the local maxima and minima of intensity, which act to enhance or suppress local maxima, depending on the sign of the nonlinear coefficient $\alpha$. We then studied the resulting nonlinear dynamics, including the focusing of Gaussian and flat-top beams.

The dynamics are very different from the regular nonlinear Schrodinger equation with focusing nonlinearity, where such a flat top beam would quickly break up into a collection of tightly-focused bright solitons. In this case, since the nonlinearity is proportional to the intensity gradient, its influence is mainly limited to the edges of the flat-top beam. 

We also uncovered some interesting connections to the physics of nonlocal nonlinear systems. Specifically, our "topological nonlinearity", when regularized, resembles a weakly nonlocal nonlinearity with a vanishing local part. Such nonlinearity leads to cusp solitons, as was previously studied in the context of plasma physics!

We hope to follow up this study with investigations of similar "topological" nonlinearities and potential experimental realizations. In the present work we speculated that similar nonlinearities may arise in the context of fluid-mediated nonlinearities and lattices undergoing Floquet modulation, but demonstrating such implementations explicitly remains an open problem for us.

Artificial Intelligence Photonics 2026 in San Sebastian: call for abstracts

The Artificial Intelligence Photonics 2026 workshop will be held at Palacio Miramar in San Sebastian, on 15-18 June, 2026. This meeting follows the first edition held in 2023 and is aimed at gathering a critical mass of people working at the intersection of AI and photonics. The preliminary list of confirmed invited speakers comprises:

• Andrea Alù, CUNY, USA
• Natalia Berloff, Oxford, UK
• Peter Bientsman, Ghent U., Belgium
• Lu Fang, Tsinghua; China
• Rachel Grange, ETH, Switzerland
• Chaoran Huang, CUHK, Hong Kong
• Aydogan Ozcan, UCLA, USA 
• Valentina Parigi, LKB, France
• Patti Stabile, Eindhoven, Netherlands
• Jelena Vuckovic, Stanford, USA

Abstract submission is open for contributed talks and posters until 1 April, 2026. The number of attendees will be strictly limited to 100. Students are more than welcome to participate.

IIT Bombay visit

Last month I had the pleasure of visiting the Department of Physics at IIT Bombay. The huge campus is a (relatively) quiet green bubble insulated from the traffic and noise of the city outside. My host was new faculty member Subhaskar Mandal, whom I first met last year towards the end of his postdoc at Nanyang Technological University.

I gave a talk on "Conical intersections and angular momentum" (slides available here). This is a long-running story which I started working on at the very beginning of my PhD studies, taking another look at it in the context of borophene lattices a few years ago. Interesting questions related to the origin and applications of  the "microscopic" orbital angular remain unanswered and worth revisiting with the current surging interest in quantum geometric effects.

I really enjoyed the other presentations on plasmonic nanocavities, bound states in the continuum, and axion topological photonic crystals, as well as interactions with the students and local faculty members. The full workshop programme is available here.