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Study achieves the optical coherent manipulation of round Rydberg states


Study achieves the optical coherent manipulation of circular Rydberg states
In the absence of the laser pulse, the Rydberg electron orbits across the nucleus on a round trajectory (blue arrow). (b) When a laser pulse transfers the inside electron to an excited orbit, the electrostatic drive pushes the Rydberg electron away on a bigger orbit, the place it rotates slower. Credit: Eva-Katharina Dietsche

Rydberg atoms are excited atoms that comprise a number of electrons with a excessive principal quantum quantity. Due to their giant measurement, long-range dipole-dipole interactions and powerful coupling to exterior fields, these atoms have proved to be promising techniques for the event of quantum applied sciences.

Despite their benefits, physicists discovered that optically accessible Rydberg states are inclined to have a brief lifetime, which limits their efficiency in quantum know-how. A attainable resolution to this drawback could possibly be to make use of round Rydberg states, with longer lifetimes, but thus far their optical detection has proved to be tough.

Researchers at ENS-University PSL, Sorbonne Université, Université Paris-Saclay and Universidade Federal de São Carlos have lately demonstrated the coherent manipulation of a round Rydberg state utilizing optical pulses. Their outcomes, outlined in a paper revealed in Nature Physics, might open new potentialities for the event of a hybrid optical-microwave platform for quantum applied sciences.

“Alkaline-earth atoms are interesting for Rydberg physics, because once the first electron is in the Rydberg state, they have a second electron that can still be used to manipulate the atom with lasers,” Sébastien Gleyzes, one of many researchers who carried out the research, instructed Phys.org. “However, one catch is that, if the Rydberg electron ‘trajectory’ (i.e., its wavefunction) is too elliptical, when the second electron is excited with the laser, the two electrons can collide, which lead to the auto-ionization of the atom.”

In their experiments, Gleyzes and his colleagues used round Rydberg states, states through which the trajectory/wavefunction of a Rydberg atom is ‘one circle away’ from the ionic core. Due to this round group, when a second electron contained in the atom is worked up, there’s a very small likelihood that it’s going to collide with the primary.

“Our initial goal was to demonstrate that we could excite the second electron without the atom ionizing,” Gleyzes stated. “However, during the course of the experiment, we observed that the transition frequency between two circular Rydberg states was different depending on whether the second electron was in an excited state or not.”

Study achieves the optical coherent manipulation of circular Rydberg states
Picture of the experimental set-up earlier than it’s sealed contained in the cryostat and cooled down with liquid helium. Credit: Eva-Katharina Dietsche.

Essentially, the researchers discovered that despite the fact that the 2 valence electrons inside a Rydberg atom stay far-off from one another in round Rydberg states, they will nonetheless ‘really feel one another’s presence’ by way of the electrostatic drive. They then confirmed that this ‘electrostatic coupling’ between the 2 electrons could possibly be used to coherently manipulate the round Rydberg state utilizing optical pulses.

“In a classical picture, the frequency at which the Rydberg electron rotates depends on the state of the ionic core electron (let’s call it ‘up’ or ‘down’),” Gleyzes defined. “We prepared the electron at given position on the orbit and waited for a time T such that the Rydberg electron makes an integer number of rotation if the ionic core is in ‘down’. To optically change the state of the Rydberg electron, we transiently send the ionic core electron into other state (‘up’) with a laser pulse.”

By sending the ionic core electron into the second desired state, the researchers slowed down the movement of the electron, which finally finally ends up on the opposite aspect of the orbit on the finish of the ready time (i.e., T). In different phrases, they have been in a position to management the state of the Rydberg electron (which fluctuated between one aspect and the opposite of the orbit) by making use of or eradicating a laser pulse.

“We thought that the alkaline earth Rydberg atoms would be interesting because one electron would be used for the quantum processes and the other electron would be used to control the motion of the atom (cool the atom or trap the atom),” Gleyzes stated. “Before our study, though, we thought that they would work independently.”

The approach to optically manipulate alkaline-earth round Rydberg states launched by this crew of researchers might open fascinating potentialities for the event of quantum know-how. In truth, their work is the primary to point out that the 2 valence electrons inside alkaline-earth Rydberg atoms should not totally impartial, thus scientists might use certainly one of them to govern the opposite or to detect the opposite’s states.

“The possibility of conditioning the fluorescence of the ionic core electron to the state of the Rydberg electron is extremely promising, for instance if one wants to measure the state of the Rydberg electron non-destructively,” Gleyzes added. “Our team’s long-term goal is to build a quantum simulator based on the circular states of alkaline-earth atoms.”


First profitable laser trapping of round Rydberg atoms


More data:
Andrea Muni et al, Optical coherent manipulation of alkaline-earth round Rydberg states, Nature Physics (2022). DOI: 10.1038/s41567-022-01519-w

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Citation:
Study achieves the optical coherent manipulation of round Rydberg states (2022, April 20)
retrieved 20 April 2022
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