🔬 Spin in Quantum Optics and Spintronics — Research Brief

Based on the provided material, here’s a structured overview of the role of spin in quantum optics, photonics, and teleportation:

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📌 What Is Spin?

Definition:

Spin is a fundamental quantum property of particles, analogous to internal angular momentum.

• Electron: spin = ±½

• Photon: spin = ±1 (right- or left-handed polarization)

Quantum role:

Spin can exist in a superposition of states (“up” and “down” simultaneously), making it an ideal qubit in quantum information systems.

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💡 The Role of Spin in Optics and Photonics

1. Polarization = Photon Spin

Light polarization is directly linked to photon spin. Controlling spin means controlling information flow in photonic circuits.

2. Exciton-Polaritons

• Hybrid quasiparticles (photon + exciton in semiconductors)

• Possess spin degrees of freedom

• Enable technologies such as: spin lasers, optical switches, quantum logic gates

3. Spin-Orbit Coupling of Light

In nanophotonic structures, photon spin can be manipulated locally — a gateway to miniaturized quantum devices.

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📡 Spin and Quantum Teleportation

Although the lab (at St. Petersburg State University) does not directly perform quantum teleportation, its research is foundational for:

• Quantum Interfaces

Spin states of photons, electrons, and polaritons can serve as mediators for transferring quantum information between systems (e.g., photonic qubits ↔ trapped atoms).

• Reliable Information Transfer

Spin states in materials (e.g., NV centers in diamond, quantum dots, polariton condensates) exhibit long coherence times — essential for storing and transporting quantum states.

• Hybrid Systems

Spin physics connects photonic, electronic, and atomic systems, enabling the creation of hybrid quantum networks — a cornerstone of the quantum internet.

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🧪 Research Directions at SPbU

1. Spin-Based Optical Chips

Encoding information in photon polarization on photonic chips.

2. Spin-Polariton Logic Elements

Using spin-polaritons for quantum computing logic circuits.

3. Topological Materials and Spin

Exploiting spin effects in topological insulators for robust information transfer.

4. Coherent Quantum Signal Generation

Leveraging spin states in polariton condensates to generate coherent quantum light sources.

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✅ Summary

While the Spin Optics Laboratory at SPbU doesn’t conduct quantum teleportation experiments directly, its pioneering work in:

• spin physics,

• exciton-polaritons, and

• nanophotonics

lays the groundwork for:

• transmitting and storing quantum states,

• building resilient communication infrastructure,

• and realizing future quantum networks.