A research collaboration between students and an academic at the School of Mathematical Sciences has been published recently and has made it to the front cover of the distinguished Journal Physical Review Letters.
The Journal, which was established in 1958, is considered one of the most well respected Journals in the field of Physics and is read throughout the world.
Students David Girolami and Tommaso Tufarelli as well as staff member Dr Gerardo Adesso have been researching,
The power of quantum uncertainty
Quantum physics never fails to impress. A century ago, Heisenberg's famous uncertainty principle revealed that there are a priori limits on how precisely we can know two complementary properties of small particles, such as their position and momentum. In this work, we show that even the measurement of a single quantity on quantum systems is affected by a fundamental uncertainty. Imagine we have two distant quantum particles, and we observe one in our lab. No matter what we choose to measure, the outcome will always be affected by quantum uncertainty in case our particle shares peculiar types of correlations with the other one. These correlations, commonly referred to as "discord", encompass and go beyond the spooky but more conventional entanglement, and have remained elusive so far. In this work we disclose an intimate link between discord and uncertainty, and then turn the tables around. Uncertainty triggered by discord is not a burden, but a resource that can be properly exploited to increase the sensitivity in estimating parameters such as magnetisation and phase.
We show that metrological schemes which involve imperfect probe states can never go too wrong if these probes have discord. The quest for real world quantum technology comes a step closer.
The full paper is available online to read.
Posted on Tuesday 18th June 2013