# The challenges of quantum computing

- December 18, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics

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**The challenges of quantum computing**

**Subject : Science and Technology**

**Context:**

- 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.

- In

**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.

- Its value is
- 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.**

**Opportunities:**

- 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.**