Quantum computing explained simply and how it works

Based on 9 web sources and a video by The Verge. TechFeedWatch is not affiliated with the creator, and all rights to the video remain theirs.

Quantum computing replaces binary bits with qubits that calculate multiple possibilities at the same time using quantum physics. While classical computers evaluate steps in sequence, quantum machines use wave interference to solve complex mathematical simulations. Practical machines face severe hardware challenges and will not replace consumer devices, though research roadmaps target fully error-corrected systems by 2029.
AI-generated illustration: Quantum computing explained simply and how it works

Quantum computing processes information using the basic rules of quantum physics. Normal computers use bits.

Instead, quantum systems use qubits (quantum bits). Qubits calculate multiple possibilities at the same time.

This approach helps machines solve specific mathematical puzzles. Regular computers cannot process these problems.

How do qubits, superposition, and entanglement work?

Qubits hold data in superposition (existing in multiple states at once). They also use entanglement (a physical link between particles). These traits allow quantum computers to process multiple possibilities at the same time.

According to Caltech Science Exchange, a standard computer bit strictly represents a 0 or a 1. A qubit can remain in a superposition of both states until an observer measures it.

According to the National Institute of Standards and Technology (NIST), quantum entanglement links two or more qubits together. Measuring one entangled qubit instantly determines the physical state of the other qubit. This connection lets quantum processors coordinate data across an interconnected network.

The primary principles of quantum processing include:

  • Superposition lets a qubit hold probabilities of zero and one simultaneously.
  • Entanglement pairs individual qubits so they behave as a unified system.
  • Measurement forces a fragile quantum state to collapse into a definite binary value.

Watch: the video

26 min video. In the video: The Verge breaks down the race to build scalable quantum chips

Quantum computers calculate probabilities instead of checking binary states

Quantum algorithms find solutions by manipulating probability waves. Wrong answers cancel out, while correct answers amplify.

According to IBM, quantum machines do not check every potential answer in a sequential line. Instead, they rely on a process called quantum interference (the way waves add together or cancel out).

Quantum interference works much like colliding waves on water. IBM explains that algorithms make computational pathways interfere with one another.

Traditional hardware evaluates binary code step by step. Understanding how quantum computing differs from classical systems requires seeing data as waves rather than simple switches. This wave-based math provides speed on complex combinatorial calculations (math problems that involve sorting through vast numbers of possible combinations).

That shift in logic makes the concept much clearer to picture. While a standard machine tests possibilities sequentially along a path, a quantum setup evaluates the entire field simultaneously. That collective approach is what unlocks such a massive jump in speed.

What problems are quantum computers designed to solve?

Quantum computers target complex mathematical problems. These tasks would take conventional supercomputers thousands of years to finish. According to MIT Physics, quantum hardware offers an advantage only for mathematically complex tasks.

These tasks include materials science and cryptanalysis (the practice of breaking encrypted codes). They also excel at molecular chemistry simulations.

Standard computers struggle to model the precise atomic interactions of molecules. Quantum computers use the same physical rules as actual atoms.

This makes chemical reactions much easier to simulate accurately. Better simulations could lead to improved batteries and new pharmaceutical treatments.

Data from MIT Physics and the National Institute of Standards and Technology highlights how classical and quantum architectures differ.

FeatureClassical ComputingQuantum Computing
Basic Data UnitBinary bit (0 or 1)Qubit (superposition of 0 and 1)
Primary StrengthEveryday consumer and office softwareMolecular simulation and cryptanalysis
Calculation StyleSequential state checksProbability wave interference
Processing TargetLinear data processingComplex combinatorial equations

Classical computers will remain standard for everyday digital tasks

Everyday devices like laptops and phones will not switch to quantum processors. Classical binary chips handle everyday software better.

According to MIT mathematics professor Peter Shor, quantum machines will never replace classical computers. Professor Peter Shor compared the tools to asking whether a car or a boat is better.

Each machine succeeds in its own distinct environment. According to MIT Physics, quantum systems offer no performance benefit for everyday computing tasks. Standard computers remain far faster and cheaper for word processing, streaming video, and running websites.

Personal computers do not need atomic physics to run apps or store files.

Classical systems remain the practical standard for several reasons:

  • Binary transistors process sequential logic with proven stability and low cost.
  • Standard microchips operate at room temperature without complex vacuum chambers.
  • Everyday consumer software does not require complex quantum physics equations.

Why are practical quantum computers so hard to build?

Practical quantum computers remain difficult to build. Qubits are delicate and lose data when exposed to slight temperature changes.

Outside heat, vibrations, and electromagnetic noise cause quantum states to collapse prematurely. Engineers must design complex error-correction techniques to keep calculations stable.

Building commercial hardware will take several more years of engineering work. According to IBM’s Quantum Development Roadmap, IBM projects delivering its first fully error-corrected quantum computer by 2029. IBM expects that machine to execute hundreds of millions of quantum operations.

Security systems must also adapt before these machines arrive. According to NIST, the agency released finalized post-quantum cryptography standards in August 2024 to defend global networks.

These new standards include ML-KEM, ML-DSA, and SLH-DSA (encryption and digital signature algorithms). They secure encrypted data before powerful quantum machines emerge.

Setting up new encryption standards early is a move I strongly support. These machines will eventually crack older security methods wide open, and attackers are already clever enough as it is. Having experienced the frustration of getting hacked myself, I know that locking down your systems beforehand is far better than scrambling after trouble hits.

The Verge breaks down the race to build scalable quantum chips

During an interview, science writer Sophia Chen stated that current quantum devices have not yet achieved any practical utility. [The Verge noted that existing quantum computers are not good for anything yet.

The Verge reported that Microsoft announced its Majorana 2 chip. This followed Microsoft CEO Satya Nadella claiming a state of matter theorized 100 years ago. Physicist Henry Legg published a peer-reviewed critique challenging the technical basis behind those hardware announcements.

Hardware scaling presents a massive mathematical gap. The Verge pointed out that Microsoft’s Majorana 1 chip carried 8 qubits. However, the company wants to reach 1 million qubits.

To explain the mechanics, The Verge compared a qubit to a spinning coin. A spinning coin holds probabilities of heads and tails before landing. The Verge also noted Google is exploring neutral atom systems (quantum setups that trap uncharged atoms with lasers).

Google is testing them alongside its superconducting Willow chip (a processor built with materials that conduct electricity without resistance at extremely cold temperatures). These tests help the company find reliable hardware architectures.

Try the numbers yourself in our Quantum Speed-up Calculator.

Frequently Asked Questions

What is quantum computing in simple terms?

According to the National Institute of Standards and Technology (NIST), quantum computers process data using qubits that exist in superpositions of zero and one rather than fixed binary states. This structure allows systems to calculate complex mathematical probabilities simultaneously instead of checking paths sequentially.

What is quantum computing with an example?

According to Caltech Science Exchange, while a normal bit is strictly a 0 or a 1, a qubit remains in a superposition of both states until measured. According to IBM, quantum systems use interference like colliding ripples on water to cancel wrong calculation paths and amplify correct answers.

What is quantum computing and why is it important?

According to MIT Physics, quantum computers provide a computational advantage for complex tasks like molecular chemistry simulation and cryptanalysis. According to NIST, their potential power is significant enough that the agency finalized new post-quantum cryptography standards in August 2024 to defend global encryption.

Sources

Jacob S. Olsen

Jacob S. Olsen

Runs TechFeedWatch, from Denmark

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