When it comes to studying transportation systems, stock markets and the weather, quantum mechanics is probably the last thing to come to mind. We have just demonstrated a proof of principle experiment that shows when it comes simulating such complex processes in the macroscopic world, quantum mechanics can provide an unexpected advantage – by drastically […]

## Thermodynamical cost of some interpretations of...

The interpretation of quantum theory is one of the longest-standing debates in physics. But is there a way to favor one over another using the rules of Thermodynamics? In this work, Adam Cabello and colleagues worked with us to see if the tools of complexity can provide an answer. The answers are preliminary, but appears […]

## Quantum Processes Which Do Not Use Coherence (P...

One of the core tenets of quantum theory is that systems can exist in superpositions of different states, now often termed “coherence.” However, only recently have scientists formulated a rigorous mathematical characterization of this property, work that has paved the way for many studies of coherence as a fundamental quantity. A crucial part of quantum […]

## Unbounded memory advantage in stochastic simula...

We know that quantum mechanics are save memory in modelling stochastic processes, but how great can this advantage be and does it scale? In our latest work, we study a family of processes where the memory advantage does indeed scale, and very impressively at that. In particular, as the amount of classical memory required to […]

## Fragile states are better for quantum metrology...

We knows that quantum information allows us to estimate certain unknown parameters to precisions beyond classical limits. The archetypal example, being the use of the NOON state – a superposition of N photons in either Mode A or Mode B – for phase estimation. Unfortunately, this same state is very fragile – if you accidentally […]

## Power of one qumode for quantum computation (Ph...

Hybrid quantum computation – where one makes simultaneous use of continuous and discrete variables at the same time, is a interesting variant of standard quantum computation. In this paper, we proposed a version of hybrid quantum computers that involved a single squeezed state, together with a reservoir of completely mixed states. This is reminiscent of […]

## Converting Coherence to Quantum Correlations (P...

Resource theories of quantum coherence is a very hot topic in quantum information of late. It seeks to capture our intuition of what it means it be quantum mechanical in single systems. This work, lead by Ma Jiajun, a third year PhD student in the group, managed to to connect coherence of quantum discord – a […]

## Power of one bit of quantum information in quan...

Deterministic quantum computation with one quantum bit (DQC1) has got plenty of attention due to demonstrating a rather surprising premise – a single gain bit of purity appears sufficient for a quantum computer to exhibit exponential speed over classical counterparts. In this article, we explored how these ideas map to metrology – where the goal […]

## How discord underlies the noise resilience of q...

The benefits of entanglement can outlast entanglement itself. In quantum illumination, entanglement is employed to better detect reflecting objects in environments so noisy that all entanglement is destroyed. Here, we show that quantum discord—a more resilient form of quantum correlations—explains the resilience of quantum illumination. We introduce a quantitative relation between the performance gain […]

## Experimental quantum processing enhancement in ...

Computer simulation of observable phenomena is an indispensable tool for engineering new technology, understanding the natural world, and studying human society. Yet the most interesting systems are often complex, such that simulating their future behaviour demands storing immense amounts of information regarding how they have behaved in the past. For increasingly complex systems, simulation becomes […]