Because molecules are large and difficult to entangle, they have long resisted physicists’ attempts to coax them into controlled states of quantum entanglement. This causes the molecules to bond closely together even though they are far apart.
Now, for the first time, two separate teams have succeeded in entangling pairs of cryogenic molecules using the same method: a microscopically precise optical “tweezer trap.”
Quantum entanglement is a strange but fundamental phenomenon in the quantum realm that physicists are trying to exploit to create the first commercial quantum computers.
All objects, from electrons to atoms to molecules to even entire galaxies, can theoretically be described as a spectrum of possibilities before they are observed. Only by measuring properties can the wheel of chance settle into a clear explanation.
When two objects are entangled, learning something about the properties of one object (rotation, position, momentum) instantly acts as a measurement of the other object, and the spinning wheels of both possibilities Stop completely.
So far, researchers have been able to entangle trapped ions, photons, atoms, and superconducting circuits in laboratory experiments. For example, three years ago, a team of researchers entangled trillions of atoms in a “hot and nasty” gas. Impressive, but not very practical.
Physicists also atoms and molecules Previously and even biological complex Found in plant cells. But controlling and manipulating individual pairs of molecules with sufficient precision for quantum computing purposes has been a more difficult task.
Molecules are difficult to cool and easily interact with their surroundings. This means that molecules easily fall out of their fragile quantum entangled states (so-called quantum entanglement states). decoherence).
An example of those interactions is as follows: dipole-dipole interaction: A method of pulling the positive end of a polar molecule towards the negative end of another molecule.
But those same properties also make molecules promising candidates for qubits in quantum computing, as they offer new computational possibilities.
“Those long-lived molecular rotational states form robust qubits, and long-range dipolar interactions between molecules quantum entanglement,” explain Based on a paper by Harvard University physicist Yicheng Bao et al.
Qubits are quantum versions of classical computing bits and can take on values of 0 or 1. On the other hand, a qubit can represent: large number of possible combinations 1 and 0 at the same time.
By entangling qubits, a quantum blur of 1s and 0s can act as a high-speed calculator with specially designed algorithms.
Molecules are more complex entities than atoms or particles, with more unique properties or states that can be successfully combined to create qubits.
“What this really means is that there are new ways to store and process quantum information.” To tell Yukai Lu, a graduate student in electrical and computer engineering at Princeton University, co-authored the second study.
“For example, molecules can vibrate or rotate in multiple modes, so two of these modes can be used to encode a qubit. If a molecular species is polar, Two molecules can interact even if they are far apart.
Both teams produced cryogenic calcium monofluoride (CaF) molecules, which they captured one by one with optical tweezers.
Using these strongly focused laser beams, the molecules were arranged in pairs, close enough that one CaF molecule could sense the long-range electric dipole interactions of its partner. This caused each pair of molecules, previously unknown, to join together in an entangled quantum state.
By precisely manipulating individual molecules, the method “opens the way to the development of new versatile platforms for quantum technologies.” write Perspectives from Augusto Smelzi, a physicist at the Italian National Research Council.
Although Smeltzi was not involved in the research, he sees the potential. By exploiting dipolar interactions in molecules, the system could one day be used to develop ultrasensitive quantum sensors that can detect ultra-weak electric fields, he says.
“Applications range from electroencephalography, which measures electrical activity in the brain, to monitoring changes in electric fields in the Earth’s crust for earthquake prediction.” Infer.