Quantum Computing: A Concise Introduction
Definition
1. Introduction
2. Quantum Principles in Quantum Computing
2.1. Hardware for Quantum Computing
2.2. Quantum Algorithms
2.3. Computational Complexity and Quantum Advantage
- Class P (Polynomial Time) consists of problems that can be solved efficiently (i.e., in polynomial time) by a classical deterministic algorithm.
- Class NP (Nondeterministic Polynomial Time) includes problems for which proposed solutions can be verified efficiently, even if finding such solutions may not be feasible in polynomial time. One of the most prominent open questions in theoretical computer science is whether P = NP.
2.4. The Power of Quantum Computing
3. Areas of Quantum Computing’s Greatest Potential Impact
3.1. Cybersecurity and Post-Quantum Cryptography
3.2. Information Retrieval
3.3. Automation
4. The Post-Quantum Future
4.1. How Will Knowledge-Based Industries Evolve?
4.2. What Is the Future of Work?
4.3. What Becomes of the Human Mind?
4.4. Quantum Ethics and Policy
5. Conclusions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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| Category | Platform | Type | Connectivity | Strengths | Limitations | Maturity |
|---|---|---|---|---|---|---|
| Hardware | Google Willow [4] | Superconducting (transmon) | Planar grid and nearest-neighbor | Fast gates; advanced calibration & benchmarking pipelines | Cryogenics; crosstalk; fidelity scaling | Research & Noisy intermediate-scale quantum computing (NISQ)-class flagship devices |
| Hardware | IBM Quantum [5] | Superconducting (transmon) | Coupling-map topologies (planar) | Cloud access; strong toolchain | Coherence & connectivity constraints typical of superconductors | Broad device family; leading NISQ access |
| Hardware | IonQ [6] | Trapped ions (hyperfine/optical) | All-to-all within a single chain | Long coherence; high single/two-qubit fidelities | Slower gates; scaling across chains needs photonic links | Commercial cloud systems; strong small to medium-circuit performance |
| Software | Qiskit [7] | SDK (Python) | IBM devices; providers for others; simulators | Rich transpiler; visualization; pulse-level access | IBM-centric by default | Actively maintained; wide community use |
| Software | Cirq [8] | SDK (Python) | Google devices and compatible simulators | Native abstractions; noise models; calibration workflows | Google-centric | Research & production tooling within Google ecosystem |
| Software | Microsoft QDK [9] | SDK (Q#, Python & C# interop) | Azure Quantum ecosystem; simulators; resource estimation | High-level Q# language; resource estimation; heterogeneous backend routing | Heavier tooling stack; best within Azure flow | Active tooling; growing backend support |
| Feature | Classical Computing | Quantum Computing |
|---|---|---|
| Basic Unit | Bit (0 or 1) | Qubit (a coherent quantum state in superposition of basis states) |
| Key Phenomena | Binary Logic | Quantum gates |
| Processing | Sequential/Parallel | Quantum parallelism with interference-based amplitude manipulation |
| Example Task | Password cracking | Grover’s algorithm; Shor’s algorithm for factoring (breaking RSA (i.e., Rivest-Shamir-Adleman) encryption) |
| Limitations | Limited by Moore’s Law | Sensitive to decoherence |
| Area of Impact | Description | Potential Benefits | Challenges & Concerns |
|---|---|---|---|
| Cybersecurity & Post-Quantum Cryptography | Quantum computing threatens traditional encryption; PQC aims to resist quantum attacks using hard mathematical problems (e.g., lattice cryptography). | More secure systems in a post-quantum world. | Existing infrastructure is vulnerable; risk of cyberwarfare. |
| Information Retrieval | Quantum-enhanced algorithms (like Grover’s) allow faster and more relevant data search and retrieval. | Rapid, precise access to information; supports complex queries. | May reduce role of libraries; risks of bias or over-reliance on “perfect” results. |
| Automation | Quantum optimization can drastically improve machine learning, logistics, and robotics. | Higher efficiency, fewer errors, optimized decision-making. | High costs, energy demands, risk of job displacement. |
| Knowledge-Based Industries | Quantum-AI systems could perform summarization, indexing, and analysis roles. | Frees humans to focus on ethics, strategy, and creativity. | Disruption of traditional professional roles. |
| Future of Work | Quantum computing boosts AI productivity across sectors. | Job creation in quantum tech; increased efficiency. | Threats to repetitive and cognitive jobs in both blue- and white-collar sectors. |
| Human Cognition & Society | Potential impact on mental engagement, purpose, and autonomy. | May liberate humans from routine tasks. | Risks of dependence, alienation, erosion of critical thinking. |
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Lund, B.D.; Shahriar, S. Quantum Computing: A Concise Introduction. Encyclopedia 2025, 5, 173. https://doi.org/10.3390/encyclopedia5040173
Lund BD, Shahriar S. Quantum Computing: A Concise Introduction. Encyclopedia. 2025; 5(4):173. https://doi.org/10.3390/encyclopedia5040173
Chicago/Turabian StyleLund, Brady D., and Sakib Shahriar. 2025. "Quantum Computing: A Concise Introduction" Encyclopedia 5, no. 4: 173. https://doi.org/10.3390/encyclopedia5040173
APA StyleLund, B. D., & Shahriar, S. (2025). Quantum Computing: A Concise Introduction. Encyclopedia, 5(4), 173. https://doi.org/10.3390/encyclopedia5040173

