When we think about charging a battery, we typically imagine that the charge flows one way. For example, when we plug our smartphones in at night, we think of the charge as flowing from the outlet into the phone鈥檚 battery.
While this holds true in the classical physics of our day-to-day world, it is typically not the case in the quantum regime.聽鈥淲hen you鈥檙e dealing with quantum, the flow of energy is actually symmetrical,鈥 explains Dr. Shabir Barzanjeh, associate professor of physics at the 草莓污视频导航's Faculty of Science.聽
鈥淭he energy bounces back and forth between the charger and battery.鈥
The smaller the scale, the more problematic this symmetry becomes. At micro and nano scales, it can greatly reduce the efficiency of the charging process. These are precisely the scales at which Barzanjeh focuses his research.
鈥淛ust like classical machines, many micro and nanodevices can be used to capture and store energy,鈥 explains Barzanjeh. 鈥淒ealing with the inefficiencies of symmetric energy flow is a roadblock in building smaller batteries that can store more energy.鈥
Barzanjeh has been studying this challenge for quite some time. Now, in a , he and his colleagues have made promising steps toward a solution. Selected as an editor highlight, the paper represents significant progress in addressing some of these miniaturization issues.
The novel process 鈥 which Barzanjeh and his University of Gdansk colleagues Borhan Ahmadi, Pawe艂 Mazurek, and Pawe艂 Horodecki proposed 鈥 relies on breaking time-reversal symmetry through nonreciprocity.
Let鈥檚 take a closer look at these quantum concepts.
Time-reversal symmetry: forwards and backwards
In time-reversal symmetry, an object or process is the same if experienced in either direction. For example, a movie played forward and backward is fundamentally the same collection of images and sounds. Similarly, energy transmission undergoes the same process if it鈥檚 flowing from an outlet to a battery, or from the battery back to the outlet.
Most systems in nature are subject to time-reversal symmetry, and this tends to be how we think of the world operating: we can walk into a room or out of it, travel to a destination and then return from it, and so on.
Nonreciprocity: a one-way street
Nonreciprocity occurs when time-reversal symmetry is broken. Suddenly, a process can only unfold one way, with no reverse possible. Imagine a movie that would completely disappear if you tried to play it backwards, or a room that you could walk into 鈥 but never out of.
The principle of nonreciprocity has long been a fundamental tool in diverse quantum technology applications. By enabling the unidirectional flow of signals and energy, it effectively suppresses the 鈥渘oise鈥 that often interferes with quantum systems.
This technique has been applied to isolate systems and information to enable quantum computing, ultra-sensitive measurement with atomic clocks, and more. But it has not been effectively applied to quantum batteries 鈥 until now.
Bringing nonreciprocity to batteries
Barzanjeh鈥檚 work and resulting paper prove the capability for using nonreciprocity in charging and leveraging quantum batteries. 鈥淚n a non-reciprocal system, all of the energy flows one way, so there is no backflow,鈥 he explains.
In the quest to miniaturize batteries for micro and nanomachines, this process is poised to help in two important ways. First, it can enable more efficient batteries in terms of charging and storage capacity. Second, it can drive further reductions in battery size. Both developments will contribute to the ongoing improvement of quantum computing and nanomachines.
鈥淚t鈥檚 exciting to do research at a university where we鈥檙e leading the way on so many quantum discoveries and innovations,鈥 says Barzanjeh. 鈥淲e are really seeing 草莓污视频导航 realizing its potential as a quantum innovator, and it鈥檚 great to be a part of that.鈥