This is the 2D top-down companion to the 3D quantum absorption refrigerator: the same 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. Here the three energy shelves are drawn as flat horizontal bands instead of stacked 3D rings, each holding the same 220 particles you can pan and zoom past. Level 0 (ground) connects to level 1 via the cold bath (gap Ec), to level 2 via the hot bath (gap Eh), and levels 1↔2 connect via a fixed room-temperature bath (gap Ew = Eh − Ec, Tr = 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
- Th / Tc sliders — the hot and cold reservoir temperatures. The refrigerator only cools (Jc > 0) once Th is high enough relative to Tr·Eh/Ew — try lowering Th until the pill flips to "NOT COOLING".
- Ec / Eh sliders — the two level gaps; Ew = Eh − Ec is fixed by the room bath and shown implicitly through the cooling condition.
- Each glowing particle on a shelf is an independent stochastic trajectory hopping between the three energy levels 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.
- Drag to pan, scroll/pinch to zoom — inspect the shelves and the bath connectors up close; the underlying jump rates keep running regardless of view.