The challenges of quantum computing
- December 18, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics
The challenges of quantum computing
Subject : Science and Technology
- In 2021 the Indian government launched a National Mission to study quantum technologies with an allocation of ₹8,000 crores; the army opened a quantum research facility in Madhya Pradesh, and the Department of Science and Technology co-launched another facility in Pune.
Quantum computer (QC):
- Quantum computers mimic the behaviour of atoms and subatomic particles to drastically increase processing speed.
- The qubit is the fundamental unit of a Quantum Computer (QC).
- These particles can exist in several states simultaneously, a puzzling phenomenon called quantum superposition.
- In Quantum superposition, quantum objects form inextricable bonds, or entangle, with one another and influence each other’s behaviours, even from large distances.
- Two or more bonded quantum objects create a delicate ecosystem called a composite quantum system.
- This means that if one object in the system is disturbed, every object with which it is entangled will also be disturbed.
How does a computer use quantum superposition?
- The bit is the fundamental unit of a classical computer.
- Its value is 1 if a corresponding transistor is on and 0 if the transistor is off.
- The transistor can be in one of two states at a time – on or off – so a bit can have one of two values at a time, 0 or 1.
- In the Qubits, instead of being either 1 or 0, the information is encoded in a superposition: say, 45% 0 plus 55% 1.
- This is entirely unlike the two separate states of 0 and 1 and is the third kind of state.
- One qubit can encode two states. Five qubits can encode 32 states. A computer with N qubits can encode 2N states – whereas a computer with N transistors can only encode 2 × N states.
- So a qubit-based computer can access more states than a transistor-based computer, and thus access more computational pathways and solutions to more complex problems.
- It’s typically a particle like an electron.
What are Transmons:
- In quantum computing, and more specifically in superconducting quantum computing, a transmon is a type of superconducting charge qubit that was designed to have reduced sensitivity to charge noise.
- Google and IBM have been known to use transmons, where pairs of bound electrons oscillate between two superconductors to designate the two states.
Challenges in their practical usage:
- Researchers face some fractious challenges.
- A practical QC needs at least 1,000 qubits. The current biggest quantum processor has 433 qubits.
- There are no theoretical limits on larger processors; the barrier is engineering-related.
- Qubits exist in superposition in specific conditions, including very low temperatures (~0.01 K), with radiation shielding and protection against physical shock. Even a minuscule shock can collapse the quantum state, a phenomenon called decoherence.
- Material or electromagnetic defects in the circuitry between qubits could also ‘corrupt’ their states and bias the eventual result.
- Researchers are yet to build QCs that completely eliminate these disturbances in systems with a few dozen qubits.
- Error correction is also tricky. The no-cloning theorem states that it’s impossible to perfectly clone the states of a qubit.
- Quantum has the potential to significantly increase the connectivity, security, and speed of the internet.
- The so-called quantum internet links quantum devices together using entanglement.
- It can provide a hack-free communication system using quantum cryptography.