Scientists have built a new type of molecular qubit that helps connect quantum computers through existing communication technologies, laying the foundation for a future quantum internet.
The new qubits contain a rare earth element called erbium, which has optical and magnetic properties that allow quantum information to be transmitted using the same wavelengths as fiber optic networks.
you may like
The research team published their findings in the journal Science on October 2nd. They said in a statement that the technology is a “promising new building block for scalable quantum technologies,” ranging from ultra-secure communications links to long-distance networks of quantum computers, often referred to as the quantum internet.
Much research has gone into building the technology needed for a quantum internet, including a new chip developed in September that helps transmit quantum signals over real-world fiber optic cables. In the new study, researchers focused on building a new type of qubit that could be useful for transmitting data.
“By demonstrating the versatility of these erbium molecular qubits, we have taken another step toward scalable quantum networks that can connect directly to today’s optical infrastructure,” David Orshalom, principal investigator on the study and professor of molecular engineering and physics at the University of Chicago, said in a statement.
Different types of qubits
Qubits are the most basic form of quantum information and act as the quantum equivalent of bits in classical computing.
However, the comparison mainly ends here. While classical bits compute with binary ones and zeros, qubits operate according to the strange rules of quantum physics and can exist in multiple states at once. This is a property known as superposition. Therefore, a pair of qubits can be 0-0, 0-1, 1-0, and 1-1 at the same time.
Qubits typically come in three forms. One is a superconducting qubit, which is made from tiny electrical circuits. Trapped ion qubits store information in charged atoms held in place by electromagnetic fields. and photonic qubits, which encode the quantum states of particles of light.
Molecular qubits use individual molecules, often built around rare earth metals whose electronic spins define their quantum states. This spin imposes a small magnetic field on the electron, and its direction defines the value of the qubit. Like regular bits, they can represent 1, 0, but they can also have both states superimposed.
you may like
What makes the new erbium-based qubit unique is that it behaves like both a spin qubit and a photonic qubit. Information can be stored magnetically and read out using optical signals.
The researchers showed in experiments that the spins of erbium atoms can be arranged in a controlled superposition. This is a key requirement for qubits to function. Because spin states affect the wavelength of light emitted by atoms, the researchers were able to read the quantum states of the qubits using standard techniques such as optical spectroscopy.
“These molecules can act as nanoscale bridges between the magnetic and optical worlds,” study co-first author Leah Weiss, a postdoctoral fellow at the University of Chicago’s Pritzker School of Molecular Engineering, said in a statement. “Information could be encoded in the magnetic states of molecules and then accessed with light at wavelengths compatible with the well-developed technologies underlying fiber optic networks and silicon photonic circuits.”
long distance quantum data
Operating at communications wavelengths has two important advantages. First, signals can be transmitted over long distances with minimal loss. This is essential for transmitting quantum data across fiber networks.
Second, light at fiber optic wavelengths easily passes through silicon. Otherwise, the data encoded in the optical signal will be absorbed and lost. Erbium-based qubits are ideal for chip-based hardware, the researchers said, because optical signals can pass through the silicon to reach detectors and other photonic components embedded below.
“The communication wavelength is the one that has the lowest rate of loss for light passing through an optical fiber, which is important if you want to reliably transmit the information encoded in a single photon (a single particle of light) out of the lab,” Orshalom told Live Science via email.
Scale is another advantage, Orshalom explained. Each qubit is constructed from a single molecule that is approximately 100,000 times smaller than a human hair. Because the structure of molecular qubits can be tailored through synthetic chemistry, it is possible to incorporate them into environments that are not possible in other environments, such as solid-state devices or inside living cells.
This level of control could help address one of quantum computing’s biggest engineering challenges: building quantum compatibility directly into existing technologies.
“Integration is an important step in scaling technology and a prominent challenge in this space,” Orshalom said. “We are working to integrate these qubits into on-chip devices, which we believe will open new frontiers in molecular control, detection, and binding.”
Source link
