News Excerpt:
Researchers are investigating simpler and more cost-effective technologies as alternatives to overcome the limitation of quantum computers operating only at very low temperatures.
Quantum Computer:
- Quantum computers are machines that use the properties of quantum physics to store data and perform computations.
- This can be extremely advantageous for certain tasks where they could vastly outperform even our best supercomputers.
- Classical computers, which include smartphones and laptops, encode information in binary “bits” that can either be 0s or 1s.
- In a quantum computer, the basic unit of memory is a quantum bit or qubit.
- A qubit can exist in one of the two states or a superposed state with contributions from both states.
- This superposition is a quantum feature that the bits in conventional computers don’t exhibit.
- However, superpositions are fragile. The fragility arises out of the interaction between the qubit and other systems.
- The more the number of interaction channels, the faster the superposition “decoheres” and the qubit ends up in one of the two states.
- Quantum computers are based on technologies that require very low temperatures and are costly, limiting their accessibility.
Basic criteria required for Qubit:
- Qubits should be identical.
- Because qubits are manufactured, some small differences are inevitable.
- It should be easy to integrate and control multiple qubits.
- This means manipulating each qubit individually (addressability) and allowing qubits to interact with each other.
- The qubit system should work reliably at room temperature for reasonable periods without losing its quantum properties.
- Numerous physical systems can be used to create qubits.
- Examples of well-researched and viable options include superconducting junctions, trapped ions, and quantum dots.
- However, these systems can only function as qubits under conditions of very low temperatures, high vacuum, or both.
Chromophores, the ‘colour molecules’:
- In the system studied by the Japanese team, zirconium serves as the metal component, while an organic molecule containing the chromophore pentacene bridges the metal atoms.
- A chromophore is an organic molecule or part of a larger molecule that absorbs light of a specific colour, giving objects containing such molecules a dominant colour.
- For example, chlorophyll in plant leaves appears green because it predominantly absorbs red and blue colours from sunlight.
Findings of the research:
- A recent collaborative study conducted by institutions in Japan achieved qubits at room temperature in a metal-organic framework (MOF).
- A MOF is a network of molecular arrangements featuring metal atoms or ions with attached organic molecules forming a repeating structure.
- In their experiment, the Japanese team found that even at room temperature, the coherence of the superposition of two four-electron states survived up to a fraction of a microsecond, which is a long duration in the current context.
- Other qubit systems require an extremely low temperature if coherence has to last this long.
Conclusion:
The development of room-temperature qubits marks a significant milestone in quantum computing, and it will invite many research groups to explore the system further.
