The Qubit in Quantum Computing

Context:  

Recently, scientists from various institutions in Japan worked together on a study reported in the journal Science Advances. 

Breakthrough in Quantum Computing With Stable Room Temperature Qubits

• The Japanese study focused on a system with zirconium as the metal component and an organic molecule containing the chromophore pentacene connecting the metal atoms.
• They discovered a way to create qubits, the building blocks of quantum computers, at room temperature using a metal-organic framework (MOF).

What Is Qubit?

• It is the fundamental unit of information in quantum computing. 
• It is a two-state (or two-level) quantum-mechanical system.
  • It uses the quantum mechanical principle of superposition to combine two states linearly.
    • This quality of superposition is unique to quantum systems as it  is not present in the bits of traditional computers. 
    • These superposed states, also referred to as coherent superpositions.
      • It plays a significant role in quantum information processing methods.

Challenges With Qubits:

• Qubits’ superposition feature is special but is fragile  due to interactions with other systems. 
• They should be the same to make a quantum device which is very difficult. 
  • They are manufactured so there are chances of small errors. 

About Chromophores

• Chromophores are molecules that absorb specific colors of light due to which it helps in giving objects their dominant color.
• For instance, the green color of numerous plant leaves results from chlorophyll, a chromophore that mainly absorbs red and blue light from sunlight.
• Chromophores cause coloration due to which it is commonly referred to as “color molecules”. 
• When a chromophore absorbs light, it enters a higher energy level known as an excited state.

• In its ground state, a chromophore molecule has a pair of electrons with opposite spins, known as a singlet configuration.
• • Singlet configuration occurs when the spins of two electrons point in opposite directions, resulting in a total spin of zero.
• Excitation involves electrons moving to higher energy levels similar  to climbing up a ladder.
  • A singlet excited state arises when electrons on different energy levels have opposite spins, while a triplet excited state occurs when electrons on different levels have spins in the same direction. 
• The process, where a singlet excited state chromophore produces two triplet excited chromophores, is called singlet fission. 
  • This energy transfer occurs as the two chromophores interact.

New Source: Thehindu

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