The top physics headlines this week included news on the pitch drop experiment, a step into micro world by scientists researching robotics and the new methods in the search for dark matter. To receive these news straight to your email, register for our email newsletter.
Dark matter search is usually associated with astrophysics or particle physics, which in turn cannot be done easily without large particle accelerators. Recent discoveries in gravity resonance spectroscopy, however, showed that it is sensitive enough to potentially act as a tool in the search for dark matter. The new technique developed by Larisa Chizhova, Professor Stefan Rotter and Professor Joachim Burgdörfer takes very slow neutrons from the strongest continuous ultracold neutron source in the world, at the ILL in Grenoble and funnels them between two parallel plates. According to quantum theory, the neutrons can only occupy discrete quantum states with energies which depend on the force that gravity exerts on the particle. By mechanically oscillating the two plates, the quantum state of the neutron can be switched. That way, the difference between the energy levels can be measured. To read the original article use the link above.
The pitch drop experiment was set up in 1927 to demonstrate that solid materials—pitch shatters if hit with a hammer—can flow like liquids. Between the beginning of the experiment in 1930 and 1988, 7 drops had fallen, at an average of one drop every eight years. “Two things changed after that – the 2000 (eighth) and 2014 (ninth) drop each took about 13 years to fall, and each collided into the decades-old pile of drops in the beaker before it could break away from the funnel,” said Professor Andrew White. The rare event was captured on video and will be analyzed by scientists responsible for the experiment.
Progress in the longest-running experiment
Thanks to new research from the University of Bristol, the development of light-driven ‘micro-robots’ came a step closer to reality. Such devices could be used for high-resolution imaging, allowing the investigation of delicate biological samples such as cells in new ways. Dr David Phillips, Professor Mervyn Miles and Dr Stephen Simpson of Bristol’s School of Physics, and colleagues are working hard towards developing the technology needed to control such micro-robots, known as optical tweezers. Optical tweezers use light to move microscopic objects such as individual cells or particles 1,000 times smaller than the width of human hair.
“This work paves the way towards the development of light-driven micro-robotics by providing a set of design rules for how complicated micro-structures will behave in light fields, and using them to design a new scanning probe imaging system that can operate inside an enclosed microfluidic chamber,” said Dr Phillips when commenting on their recent paper.