A child on a swing can keep the swing in motion by repeatedly standing up and squatting down. This movement changes the frequency of the swings and amplifies them. This simple concept—known as parametric amplification—finds use also in modern quantum physics.
Tag: Quantum physics
January in quantum physics
The beginning of the year was filled with great physics. Lots of interesting theory has been done, including by me (but more details on that later). But today I want to talk about three experiments that push our abilities to control matter using light into new regimes. In two of them, scientists were able to observe quantum effects in the motion of levitated objects for the first time. In the third one, the authors used their incredible control of single atoms to create a very thin and light mirror.
Is the Moon in the sky when you’re not looking?
If you find quantum physics hard to understand (or accept), rest assured that you are not alone. Even many physicists (including Albert Einstein, one of its founding fathers) refused to acknowledge that our world can behave so strangely. That atoms or electrons can be at two places at once or that it does not always… Continue reading Is the Moon in the sky when you’re not looking?
How well can we measure position?
It is a well-known fact in quantum physics that the position and momentum of an object (e.g., a single atom or a vibrating mirror) cannot be known with an arbitrary precision. The more we know about the position of a mirror, the less we know about how fast it is moving and vice versa. This… Continue reading How well can we measure position?
Connecting superconducting quantum computers with light
Entanglement is a peculiar feature of quantum systems that makes them behave as if they were sitting directly next to each other even if they are kilometres away. Such behaviour does not occur in classical physics. Classical particles can affect each other through fields -- such as the gravitational or electromagnetic field -- but these fields propagate with… Continue reading Connecting superconducting quantum computers with light
Through the looking glass
One of the things I love about physics is how it changes the way one sees the world. As one starts to think about some basic things very differently. Then even such a simple act as measurement is a complicated process which can even be used to manipulate physical systems.
The joys of theoretical physics
Have you always thought mathematics is dull and complicated? You are certainly not alone. But there is a lot of beauty hidden in it and in the way it describes our world. Theoretical physics is all about using maths to describe nature. As the universe we live in is vast and filled with myriads of… Continue reading The joys of theoretical physics
How to measure time
Precise timekeeping is crucial for many of our daily activities. High-speed communication (on the internet or in a mobile phone network), satellite navigation, and many other tasks require time synchronisation over long distances to work properly. But how is time measured? And can quantum physics help reach better accuracies? The basic idea behind measuring time is… Continue reading How to measure time
New page on the basics of quantum physics
Do you have absolutely no knowledge about quantum physics? Do you want to get at least a basic understanding about what it is, why it is important, or how it can be relevant to everyday life? I just added a new page that tries to explain some of these basic questions in (I hope) an… Continue reading New page on the basics of quantum physics
Simplifying quantum systems
claimtoken-552906769c445 I already talked about using measurements and feedback in quantum physics and how these tools can be used to prepare interesting quantum states. But it is not an easy task -- experimental realisations require ultrafast electronics to apply feedback in real time. And theoretical analyses? Those are not easy either. Take a simple example -- an… Continue reading Simplifying quantum systems