For the first time, two atomic clocks have been successfully connected via quantum entanglement by Oxford University physicists. This accomplishment has the potential to bring these clocks closer to the basic precision limit defined by quantum physics.
The extremely steady and predictable vibrating patterns of atoms are measured by atomic clocks to maintain time. For example, the oscillation frequency of a cesium-133 atom is precisely 9,192,631,770 cycles per second. This frequency has been used to define the second officially since 1967, establishing both national and international timekeeping standards.
However, there is always space for development. Oxford researchers have now shown how to further improve the precision of optical atomic clocks, which have the potential to outperform cesium atomic clocks. Optical atomic clocks employ visible light and elements like ytterbium. To do this, one must make use of quantum entanglement, an eerie phenomenon.
Particles can entangle themselves so much that, regardless of their distance from one another, altering or measuring one will immediately impact the other. The two particles may theoretically be on opposite corners of the universe and still instantly affect one another. Although Einstein was notably spooked by the idea, it has been proved experimentally for many years.
MIT physicists have previously used quantum entanglement to entanglement a cloud of atoms within a single device in order to increase the accuracy of atomic clocks. Now, from across the room, the Oxford team has managed to entangle two different atomic clocks with one another.
There was just one strontium ion in every atomic clock. After splitting a laser beam in half, each beam is modified in the same way and transmitted into an atomic clock to strike strontium ions. This causes the ions to get entangled in a quantum entanglement even though they are only 2 meters (6.6 feet) away.
In the end, the first quantum network of entangled atomic clocks is produced, which may make time measurement more accurate than before. The measurements’ uncertainty was lowered by a factor of two by the researchers.
Entangled atomic clock networks may even be able to exceed the Standard Quantum Limit (SQL), according to the study. The SQL is caused by random quantum fluctuations that cause interference with measurements. Above that point, the precision might begin to approach the Heisenberg Limit, a rigid boundary established by the fundamental principles of quantum mechanics.
With the particular configuration utilized, which was intended for quantum computing studies, this is still unattainable. According to the team, a dedicated network of quantum-entangled atomic clocks might start to investigate important physics mysteries like dark matter and fundamental constants.
The study’s co-author, Dr. Raghavendra Srinivas, stated, “We hope that the techniques shown here might someday improve state-of-the-art systems, even though our result is very much a proof-of-principle and the absolute precision we achieve is a few orders of magnitude below the state of the art.” Entanglement will eventually be necessary because it offers a route to the highest level of precision permitted by quantum theory.
