Microsoft Majorana
Microsoft announced Feb 19, 2025: Majorana 1 Explained: The Path to a Million Qubits, Microsoft’s Majorana 1 chip carves new path for quantum computing.
- Qubits. Hard to make qubits sustainiable and reliable.
- Ettore Majorana (1906-1938) topological state, allow us to scale millons qubits on a chip.
Topological quantum computing

- Methods - 2-Level systems: Frequency of charge oscillation; Energy levels of an atom; Path photon takes; Number of photons; Electron spin or charge; Spin of an atom.
- Method - Topological (Quasi) Qubit : made from many electrons working together (collective behaviour of electrons) - Marjorana zero mode / Marjorana particle, which a energy gap to protect qubit from noise.
- Bit : odd or even number of electrons.
- Need the right combination of materials, in the right shape, which is difficult. Building steps : (1) Material growth step; (2) Nanofabrication step.
- The objective of the delicated fabrication is to make the marjorana particle pair separate, to protect the energy gap.
Quantum Computing
The Map of Quantum Computing - Quantum Computing Explained
- Qubit - quantum wave function.
- Entanglement : All the qubits entangled together, with N qubits, the number of possible states is $2^N$. A quantum computer is in all the super states at the same time.
- Interference : quantum wavefunctions forms overall wavefunction, which reflects the probability distribution.
- When computing : (1) use instructive interference to increase the probabilities of the correct answer; (2) use destructive interference to decrease teh probabilities of the incorrect answer.
Quantum Algorithms. Example: Shor's algorithm - factorisation of large number (used for encryption). Scale of log(N) ($2^{N/2}$ for classic computer), Quantum complexity theory.
Applications : Quantum simulation, Optimization, Machine Learning.
Models of quantum computing.
- Universal methods (Mathematically equivalent):
- Gate (Circuit) Model : apply gates, which rotating the qubit’s directions, to process algorithm.
- Measurement based (on-way) Model.
- Abiabatic Model : make the minmum energy state be the answer of the problem.
- Quantum annealing : also energy minimization, but not universal.
- Topological quantum computing : Majorana zero-mode quasi-particle. More stable, but not observed yet.
Physical realisations (2-Level systems).
- Obstacles : Decoherence (entangled to environment); Noise; Scalability.
- Quantum error correction (use a group of qubits).
- Superconducting quantum computers.
- Quantum dot quantum computers (Silicon spin quantum computers).
- Linear optical quantum compters, light system.
- Trapped ion quantum computers.
- Colour center quantum cimputer : qubits embedded in materials.
- Neutral atoms in optical lattices : trapped atoms in optical lattice, coolde to millionths of a kelvin.
- Others : Electron-on-helium qubit, Cavity quantum electrodynamics, Magnetic molecule, Nuclear magnetic resonance.
Qiskit.org