The 33-year-old professor of the Chinese University of Science and Technology re-published Nature: Quantum entanglement between atoms and molecules

This molecular lym on quantum control was reported in a paper published May 20 in Nature, the world’s leading academic journal. Since molecular bit frequencies can be selected over a wide range, the paper believes that similar mechanisms can be used as “converters” in hybrid quantum information systems, just as classic computers require physical vectors that are compatible with different attributes such as processors, discs, hard drives, etc. for information processing, storage, or transmission.

Under laser control, a molecular ion trapped in an electromagnetic field trap and an atomic ion have a magical entanglement effect.

Quantum entanglement is the “ghostly long-range action” in Einstein’s mouth, and the two quantums in the entangled state are related no matter how far apart, one of which changes (such as when people measure it) and the other changes instantaneously.

It is relatively easy to entangle photons, as long as they hit them on to a special crystal line, it becomes a pair of entangled photons. If the spin direction of one of the photons is “upward”, the spin direction of the other photon entangled with it must be “downward”.

The interaction between photons and atoms, the energy level after the absorption or loss of photons, can be raised or decreased, this interaction can be used to entangle photons and atoms, and even through the continuous interaction of one photon to entangle multiple atoms.

In practice, to achieve such precise manipulation and measurement of the atom, the key is to hold the atom fixed to reduce its vibration. Although scientists’ dream of “motionless” atoms is not yet possible, they have come up with a number of effective ways to “calm down” the atom. For example, an electric magnetic field holds an atomic ion that loses an electron and is positively charged, and then uses a laser to exert resistance.

Similar cold atomic technology has made many applications in the fields of atomic clock and quantum computing. Molecules, on the other hand, are made up of multiple atoms in different postures, and the structure is more complex and more difficult to control. Molecules like atoms have different energy levels, can be different angles and speeds of rotation, vibration, so there is more information in the dimensions, can the molecule achieve similar play?

In 2017, the U.S. Institute of Standard Technology (NIST) captured two calcium ions that are one millionth apart. Hydrogen leaks into the vacuum chamber until a calcium ion and a hydrogen atom combine to form a calcium hydrogenated molecular ion. The researchers then used lasers to cool atomic ions and made infrared laser pulses to drive molecules to transition between specific two in more than 100 possible rotational states, just as a diode would express “0” or “1”.

This paper is an extension of the above-mentioned “quantum logic spectroscopy” technique, which uses a set of blue and infrared lasers of different intensity, direction and pulse sequences to cool, entangle, and read molecular ions.

The 33-year-old professor of the Chinese University of Science and Technology re-published Nature: Quantum entanglement between atoms and molecules

Experimental design

Similarly, two ions are first captured, which, because of the positive electricity mutual exclusion, constitute a spring-like dynamic lock. By increasing energy by laser, molecules are superimposed on low-energy and high-energy rotational states, causing two ions to oscillate together. The state of the molecule is entangled with this movement.

Finally, the two sets of hydroxide calcium ions (CaH-plus) are then entangled with the two energy levels of calcium ions by laser-induced high-low energy state.

The 33-year-old professor of the Chinese University of Science and Technology re-published Nature: Quantum entanglement between atoms and molecules

Energy-level conversion of calcium ions and calcium hydrodeations (CaH-)

In this experiment, molecular bits can be converted from low-frequency (13.4 kHz) to high-frequency states (8.55 trillion Hz).

The team believes that by using different elements to form different molecules, a wider range of molecular bit properties can be selected, with potential applications in quantum information science, quantum sensors, quantum chemistry and other fields.

The first author of the paper and the correspondent is Lin Yiheng, a professor at the School of Physics of the University of Science and Technology of China. Three other authors, David R. Leibrandt, Dietrich Leibfried and Chin-wen Chou, are from the NIST Time and Frequency Department.

The 33-year-old professor of the Chinese University of Science and Technology re-published Nature: Quantum entanglement between atoms and molecules

NIST researcher Chin-wen Chou is debugging the laser

According to public records, Lin Yiheng was born in Guangdong in December 1986 and graduated from the University of Science and Technology in 2009 at the University of Colorado boulder, where he received his Ph.D. from Nobel Prize-winning physics laureate David Wineland in 2015. He was also an Assistant Researcher at NIST from 2010 to 2015.

The 33-year-old professor of the Chinese University of Science and Technology re-published Nature: Quantum entanglement between atoms and molecules

Lin Yiheng

Vanland has made great contributions to improving the accuracy of spectral measurement, which has greatly promoted the development of higher-precision atomic clock technology and the development of the technology of control with atomic quantum state. Vanland, which trapped charged atoms or ions and controlled and measured them through light or photons, was awarded the Nobel Prize in 2012.

Prior to that, Lin Yiheng has been involved in 9 Physical Review Letters (PRL), 2 Nature and 1 Science paper. However, it is the first time that a paper in Nature has been published as the first author.