In a scientific breakthrough at Princeton University, Lawrence Cheuk's team has achieved an achievement in quantum physics: the entanglement of individual molecules. This research, published in the journal Science, reveals a fascinating phenomenon: entangled molecules can remain physically connected despite being separated from each other over large distances.
Quantum entanglement, a key concept in quantum mechanics, implies that two particles are connected in such a way that the state of one immediately affects the other, regardless of the distance between them. Albert Einstein described it as a “ghostly action from a distance,” an idea that, although initially controversial, is now widely accepted by scientists.
The Princeton experiment took a new step by using molecules. Molecules are more complex than atoms and offer additional ways to store and process information. For example, the vibration and rotation modes of a molecule can be used to encode information.
To conduct their experiment, the researchers cooled the molecules to extremely low temperatures, using the laws of quantum mechanics. They used “optical tweezers,” a type of very precise laser beam, to manipulate each molecule individually. They then managed to encode qubits (the bits of quantum computing) in these molecules.
To create the entanglement, the researchers used microwave pulses to create interactions between the molecules. This method allowed them to connect two molecules in an entangled state.
This research opens promising perspectives for quantum science, particularly for the simulation of complex systems in which emerging phenomena such as new types of magnetism could be studied. It is crucial for the future development of quantum computing and the simulation of complex materials.
Another research group led by John Doyle, Kang-Kuen Ni and Wolfgang Ketterle came to similar results, confirming the reliability and significance of these results.
The quantum computer
A quantum computer is a type of computer that uses the principles of quantum mechanics to process information. Unlike classical computers, which use bits as the basic unit of information (representing 0 or 1), quantum computers use qubits. A qubit can be in state 0, 1, or any superposition of these two states. This ability to be in multiple states simultaneously, along with quantum entanglement, gives quantum computers significantly greater computing power potential than classical computers for certain specific tasks.
Quantum computers are particularly promising for solving complex and computationally intensive problems such as factoring large numbers, searching unstructured databases, and simulating quantum systems, which would be extremely difficult, if not impossible, for classical computers.
One of the key concepts of quantum computing is superposition, which allows a qubit to perform multiple calculations at the same time. Quantum entanglement, another key phenomenon, allows qubits to influence each other regardless of the distance between them. These properties make quantum computers incredibly efficient for certain types of calculations.
However, building and maintaining stable and reliable quantum computers is a major challenge. Qubits are extremely sensitive to environmental perturbations, a problem known as “quantum decoherence.” In addition, it is also a challenge to accurately read (measure) quantum states without disturbing the system.
Despite these challenges, advances in the field of quantum computing are rapid and have the potential to transform fields such as cryptography, optimization, quantum chemistry and materials research, paving the way for technological advances and important scientists.