# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DZc0waOAJWV
- **Gondola URL:** https://gondola.cc/posts/66591649-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/7beb37aac4.jpg
- **Posted:** 2026-06-11T15:20:08.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

The image you picture when someone says “quantum computer” is almost certainly wrong. That gleaming golden chandelier of coiled tubes and stacked plates is not the computer. It is the refrigerator. The actual processor is a chip smaller than a fingernail, bolted to the very bottom, and everything above it exists to keep that chip colder than the void between galaxies.

Superconducting qubits, the transmon variety used across most of the field, only behave quantum mechanically when thermal noise falls below their operating energy. A qubit transition near 5 GHz corresponds to a temperature of roughly 240 mK. To hold the qubit reliably in its ground state, the chip is cooled to about 10 to 15 millikelvin, a hundredth of a degree above absolute zero.

That cold comes from a dilution refrigerator, and the physics is elegant:

	•	Helium-3 and helium-4 separate into two phases below 870 mK
	•	Pumping helium-3 across the phase boundary costs energy, pulling heat from the chip
	•	Cooling power scales with circulation rate, not with brute compression

The chandelier is a thermal staircase. Each plate is a stage: 50 K, 4 K, 1 K, 100 mK, then the mixing chamber at base. The gold-plated copper is chosen for thermal conductance, not looks.

The coaxial lines are the unsung part:

	•	Each line carries microwave pulses that drive and read the qubits
	•	Attenuators sit at every stage to strip thermal photons leaking down from warmer levels
	•	Without that staged attenuation, room-temperature noise would scramble the quantum state instantly

So most of what you are looking at is plumbing and noise management. The computation itself happens on the silent, invisible chip at the cold heart of it all.

#stemantics #quantumcomputing #cryogenics #superconductivity #physics

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## Tags

quantumcomputing, superconductivity, cryogenics, physics, stemantics

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