Quantum Absorption Refrigerator

Bath Temperatures

Hot bath T_h 3.00

Cold bath T_c 0.30

Level Spacing

Cold gap E_c (0↔1) 0.60

Hot gap E_h (0↔2) 2.20

Refrigerator State

COOLING

Cooling power J_c (heat pulled from cold bath)

0.00

COP = J_c/J_h

0.00

Entropy rate dS/dt

0.00

p₀ (ground)

p₁ (cold level)

p₂ (hot level)

How it works

A quantum absorption refrigerator is a three-level system wired to three independent thermal baths with no external work input at all — the temperature difference between the hot and room baths alone pumps heat out of the cold bath. Level 0 (ground) connects to level 1 via the cold bath (gap E_c), to level 2 via the hot bath (gap E_h), and levels 1↔2 connect via a fixed room-temperature bath (gap E_w = E_h − E_c, T_r = 1).

Detailed balance per bath (k_B = ħ = 1):
  k↑(i→j) / k↓(j→i) = exp(−ΔE / T_bath)

Steady state populations p0,p1,p2 solve:
  dp_i/dt = Σ_j [k(j→i) p_j − k(i→j) p_i] = 0,  Σp_i = 1

Heat current from bath b (positive = flows INTO the qubit):
  J_c = E_c·(k01↑p0 − k10↓p1)
  J_h = E_h·(k02↑p0 − k20↓p2)
  J_r = E_w·(k12↑p1 − k21↓p2)   with  J_c + J_h + J_r ≈ 0

Entropy production (2nd law, always ≥ 0):
  dS/dt = −J_c/T_c − J_h/T_h − J_r/T_r ≥ 0

T_h / T_c sliders — the hot and cold reservoir temperatures. The refrigerator only cools (J_c > 0) once T_h is high enough relative to T_r·E_h/E_w — try lowering T_h until the pill flips to "NOT COOLING".
E_c / E_h sliders — the two level gaps; E_w = E_h − E_c is fixed by the room bath and shown implicitly through the cooling condition.
Each glowing particle on the canvas is an independent stochastic trajectory hopping between the three energy shelves using the exact rates above — a Monte-Carlo unravelling of the same master equation used in real three-level maser / NV-center absorption-fridge proposals (Palao–Kosloff–Gordon; Levy–Kosloff).
No moving parts, no external work stroke — cooling is driven purely by the flow of heat from hot to room, exactly like a gas-absorption fridge, but built from a single quantum system.

Level 0 (ground) Level 1 (cold gap) Level 2 (hot gap)

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