We are almost at the end of 2022.
With 2023 quickly approaching, there will be plenty of quantum computing news and articles showcasing new products and concepts. The year 2022 was exciting and set the stage for new product announcements in 2023. One of my favorite online resources is "Nature," where all the latest exciting announcements are published. I was intrigued by this story. This picture credits to Aalto University Quantum lab. Measurement without interaction is the topic of this post.
Measurement requires interaction with something, right? What if we didn't touch, poke, or look at something? Quantum physics allows you to do this. In this article in Nature magazine, physicists at Aalto University explain their findings. Quantum Computing is one step closer to becoming a reality. In this method, lasers and mirrors are not used to measure. As a general rule, in order to measure something, we have to interact with it. You can't look at something without touching it, whether it's a prod or poke, or using a shower of light, or an echo of sound. Aalto University in Finland proposes a way to 'see' microwave pulses without absorption and re-emission of light waves. There's no mediating particle in this measurement, so it's an interaction-free measurement. It offers new ways to accurately measure anything when we need an accurate readout for quantum computing. But 'Looking without touching' isn't a groundbreaking concept. Current research reveals you can split neatly aligned waves of light through different paths and compare their journeys without evoking the particle-like behavior of light. It means that, by splitting neatly aligned waves of light through different paths and then comparing their journeys, physicists have demonstrated it's possible to harness the wave-like nature of light without evoking its particle-like behavior.
According to Aalto University, "interaction-free measurement is a fundamental quantum effect whereby the presence of a photosensitive object is determined without irreversible photon absorption."
Here "we propose the concept of coherent interaction-free detection and demonstrate it experimentally using a three-level superconducting transmon circuit", proposed in the publication (see link below).
Specifically, this paper proposes (CIFD)coherent interaction-free detection, which is demonstrated experimentally using a three-level superconducting transmon circuit (STC).
Exactly how do they do it?
For the complex setup to work, they relied on quantum coherence - the ability for objects to occupy two states at the same time, like Schrödinger's cat. What it entailed was a complex setup that relied on quantum coherence, which lets objects occupy two states at once.
"We had to adapt the concept to the different experimental tools available for superconducting devices," says quantum physicist Gheorghe Sorin Paraoanu, from Aalto University in Finland.
Added Gheorghe:
"Because of that, we also had to change the standard interaction-free protocol in a crucial way. We added another layer of quantumness by using a higher energy level of the transmon. Then, we used the quantum coherence of the resulting three-level system as a resource."
What he is saying is the standard interaction-free protocol also had to be altered in a crucial way. They added another layer of quantumness by using a higher energy level of the transmon and then used the quantum coherence of the resulting three-level system, for measurement."
Theoretical physics backs it up.
They used theoretical models to support their experiments. Scientists call it the "Quantum Advantage", the capability of quantum devices to extend beyond what's possible with classical devices.
The document can be viewed online or downloaded directly from the links below.
Aalto University is a public research university located in Espoo, Finland. It was established in 2010 as a merger of three major Finnish universities: the Helsinki University of Technology, the Helsinki School of Economics and the University of Art and Design Helsinki.
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