Preprints

Quantum Processes Which Do Not Use Coherence (Phys. Rev. X 6, 041028)

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 ... Read moreQuantum Processes Which Do Not Use Coherence (Phys. Rev. X 6, 041028)

Fragile states are better for quantum metrology (New Preprint)

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 ... Read moreFragile states are better for quantum metrology (New Preprint)

Power of one qumode for quantum computation (Phys. Rev. A 93, 040304)

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 ... Read morePower of one qumode for quantum computation (Phys. Rev. A 93, 040304)

Converting Coherence to Quantum Correlations (Phys. Rev. Lett. 116, 160407)

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 ... Read moreConverting Coherence to Quantum Correlations (Phys. Rev. Lett. 116, 160407)

Power of one bit of quantum information in quantum Metrology (Physical Review A 93, 040304)

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 ... Read morePower of one bit of quantum information in quantum Metrology (Physical Review A 93, 040304)

How discord underlies the noise resilience of quantum illumination (New Journal of Physics, 18, 4)

  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 ... Read moreHow discord underlies the noise resilience of quantum illumination (New Journal of Physics, 18, 4)

Experimental quantum processing enhancement in modelling stochastic processes (New Preprint)

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 ... Read moreExperimental quantum processing enhancement in modelling stochastic processes (New Preprint)

Using quantum theory to reduce the complexity of input-output processes (New Preprint)

We understand all natural things around us by their input-response behavior, for example we perceive neurological networks as transducing sensory inputs to electrical impulses known as spike trains, meanwhile photosynthesis is a mechanism for converting electro-magnetic energy to chemical energy. In this preprint, we ask whether our understanding of such phenomena depend on the information theory ... Read moreUsing quantum theory to reduce the complexity of input-output processes (New Preprint)

The classical-quantum divergence of complexity in the Ising spin chain (New Preprint)

Can quantum information fundamentally change the way we perceive what is complex? In our latest preprint, we generalized a widely-used measure of complexity – the statistical complexity – to the quantum regime. Statistical complexity quantifies the minimal classical information we must store about a process to simulate its future behaviour. We construct a quantum variant ... Read moreThe classical-quantum divergence of complexity in the Ising spin chain (New Preprint)

Converting Coherence to Quantum Correlations (New Preprint)

Recent results in quantum information theory characterize quantum coherence in the context of resource theories. Here, we study the relation between quantum coherence and quantum discord, a kind of quantum correlation which appears even in non-entangled states. We prove that the creation of quantum discord with multipartite incoherent operations is bounded by the amount of quantum coherence ... Read moreConverting Coherence to Quantum Correlations (New Preprint)