Researchers have found a way to use light and a single electron to communicate with a cloud of quantum pulses and to sense their behavior, making it possible to detect a single quantum stroke in a thick cloud.
The researchers, from Cambridge University, were able to inject a ‘needle’ of sensitive oceanic information into a ‘grass stack’ of 100,000 nuclei. Using lasers to control an electron, the researchers could use that electron to control the behavior of the haystack, making it easier to find the needle. They were able to locate the ‘needle’ with an accuracy of 1.9 parts per million: high enough to detect a single quantum beat in this large ensemble.
The approach makes it possible to send highly sensitive quantum information to a nuclear system for storage, and to verify its printing with minimal disruption, an important step in the development of a quantum web based on quantum light sources. . The results are reported in the journal Physics of nature.
The first quantum computers – which use subatomic grains to behave far superior to the most powerful supercomputers – are on the horizon. However, reducing the full potential requires a method on the network: quantum internet. Light channels that transmit quantum information promise candidates for quantum internet, and currently a quantum light source is no better than the quantum dot semiconductor: tiny crystals that are mostly artificial atoms.
However, one thing stands out in the form of quantum dots and quantum interfaces: the ability to store quantum information for a period of time at stage positions across the network.
“The solution to this problem is to store the fragile quantum information by hiding it in the cloud of 100,000 atomic nuclei contained in each quantum dot, like a needle in a haystack,” said Professor Mete Atatüre of Cambridge’s Cavendish Laboratory , who led the research. “But if we try to communicate with these nuclei as we interact with pieces, they tend to move at random, creating a sound system.”
The cloud of quantum pulses contained in a quantum dot usually does not work in a collection state, making it a challenge to get information in or out of them. However, Atatüre and his colleagues showed that in 2019, when cooled to ultra-low temperatures also using light, these nuclei can be made to form ‘quantum dances’ together, significantly reducing the there is noise in the system.
Now, they have unveiled another basic step towards storing and receiving quantum information in the nuclei. By controlling the collection state of the 100,000 nuclei, they were able to detect that the quantum information as a ‘quantum bit flipped’ at an ultra-high precision of 1.9 parts per million: enough to see one stroke in the cloud of nuclei.
“Technically there is a huge demand for this,” said Atatüre, who is also a Fellow of St. John’s College. “We have no way of ‘talking’ to the cloud and the cloud has no way of talking to us. But the thing we can talk to is the electricity: we can communicate with him like that dog that is a shepherd sheep. ”
Using the light from a laser, the researchers will be able to communicate with an electron, which then communicates with spins, or sexual square momentum, of the nuclei.
By talking to the electron, the chaotic ensemble of spins begins to cool and gather around the scattering electron; out of this more ordered state, the electron can generate spinning waves in the nuclei.
“If we think of our cloud spins as a herd of 100,000 randomly moving sheep, it’s hard to see one sheep suddenly changing direction,” Atatüre said. “But if the whole herd is moving like a well-defined wave, then one sheep change is a very obvious change.”
In other words, by injecting a spinning wave made of a single nuclear spin into the ensemble it is easier to find a single nuclear spinning spin among 100,000 nuclear spins.
Using this method, the researchers are able to send information to the quantum clip and ‘listen in’ on what the spins say with very little distraction, down to the basic limit set with quantum mechanics.
“Having harnessed this ability of control and sensing across this vast ensemble of nuclei, our next step is to demonstrate the storage and retrieval of an irregular quantum piece from the nuclear spinning disk,” said the co-author Daniel Jackson, PhD student at Cavendish Laboratory.
“This step will complete light-related quantum memory – a key building block on the road to the realization of the quantum internet,” said co-author Dorian Gangloff, a Research Fellow at the College of St. John’s.
In addition to the potential use for quantum internet in the future, the approach could also be useful in the development of hard-state quantum computing.
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The research was supported in part by the European Research Council (ERC), the Engineering and Physical Sciences Research Council (EPSRC) and the Royal Society.
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