Initial version

# [TECH] Quantum Computing Hardware
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**Quantum Computing Hardware** implements quantum bits (qubits) in physical systems — superconducting circuits, trapped ions, photons, neutral atoms — with sufficient coherence and fidelity to run quantum algorithms.
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## Overview
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The leading platforms: **superconducting qubits** (IBM, Google) — fast gates, chip-based, currently 100–1000 physical qubits; **trapped ions** (IonQ, Quantinuum) — high fidelity (>99.9%), all-to-all connectivity; **neutral atoms** (QuEra) — reconfigurable arrays, 1000+ qubits demonstrated; **photonic** (Xanadu, PsiQuantum). Google's Sycamore (2019) claimed quantum supremacy for a specific sampling task. IBM's Condor (2023, 1121 qubits) and Heron processors pursue fault tolerance. Fault-tolerant quantum computing (requiring ~1M physical qubits per logical qubit for surface code) is estimated 10–20 years away.
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## Key Actors
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- **Companies**: IBM (Quantum, 2016), Google Quantum AI (2012), IonQ (2015), Quantinuum (2021), QuEra (2018), Xanadu (2016), Rigetti (2013)
- **Investors**: $35B+ invested in quantum computing globally (2015–2023, McKinsey)
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## Key Patents
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IBM, Google, and IonQ hold the largest quantum computing patent portfolios (thousands of patents across qubit design, control electronics, error correction).
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## Economic Value
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Current market: **$1.3 billion/year** (2023, IDC). McKinsey projects $170B–$450B by 2035 from pharmaceutical, chemical, financial, and logistics applications.
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## Notes
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McKinsey *Quantum Technology Monitor* 2023. IDC *Quantum Computing Market Forecast* 2023. The technology is pre-commercial in most applications; economic projections are highly uncertain.
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# Parents
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* [SCI] BCS Superconductivity⏎