Temporada 2 · Cartas desde el Polvo Marciano · JVV-T2-12
Physics of the commons: economising entropy in quantum networks
I Why talk about “commons” in the qubit era?
Quantum networks —infrastructures of entangled-light repeaters, spin memories, diamond cryostats— devour cryogenic energy, produce waste heat and occupy a limited photonic spectrum .
As once happened with radio or GEO satellites, the key resource is no longer the optical fibre but entropy: how much quantum coherence (order) we have left before thermal noise dissolves it.
The quantum commons = a global reserve of low entropy that everybody wants to use (banks, science, activists) and nobody owns outright.
II The magnitudes that govern the “market in order”
| Parameter | What it means | Physical limit 2025 |
|---|---|---|
| Fidelity (F) | Purity of the entangled pairs | 94 % on a metro repeater; 88 % by satellite |
| Key rate (R) | good QKD bits/sec | 1–10 Mbit/s on 400 km of fibre |
| Thermal pressure (T) | Watts generated by cryogenics | 40 W per NV-center node |
| Decoherence window (Δt) | Time before collapse | 1.2 s in a trapped ion, < 0.5 s in diamond |
Every app (payments, quantum telescopes, DAOs) “burns” F, R, Δt and adds heat. With no rules, the tragedy of the commons arrives: global fidelity ↓; everybody loses.
III A proposed Common Entropy Protocol (CEP-25)
-
01
Public fidelity counter
– Nodes report F and Δt every minute; an open dashboard shows the “coherence” consumed per network. -
02
Dynamic quota
– If global fidelity drops < 90 %, the least critical contracts (quantum art streaming, RNG games) pause automatically. -
03
Enthalpic tax
– Every watt of cryogenics pays a fee into a reusable-heat fund (district heating or algae farms). -
04
A “noise quota” (NRU) market
– Tokens representing the right to inject X dB of noise; high-priority projects buy NRU, and the funds go to improving the repeaters.
IV Who wins, who loses
| Actor | Benefit under CEP-25 | New friction |
|---|---|---|
| Banks and CBDCs | Stable fidelity guarantees QKD | The cost of NRU rises at trading peaks |
| Scientists (quantum telescopes) | A guaranteed Δt window for neutron-star measurements | They must schedule observations for low-congestion hours |
| XR start-ups | Access to Q-RNG at a reduced price in off-peak hours | 24/7 streaming is not viable without paying a premium |
| States | A clear metric for allocating photonic spectrum | They lose the option of saturating the network “for free” with espionage |
V Rio–Lisbon mini-pilot (2025–2027)
- Objective: link the South Atlantic's quantum repeaters to Europe; apply CEP-25 in real time.
-
Early results:
– Cryogenic consumption ↓ 12 % thanks to the enthalpic tax recirculated into ORC turbines.
– Mean fidelity ↑ 3 % because the NRU market pushed the “noisy” apps into the small hours.
– The public counter drew climate auditors; social pressure forced the publication of a waste-heat reuse plan.
VI Risks and shields
-
Quota capture – Large operators buy NRU cheap in a crisis and choke the NGOs.
› Mitigation: a per-organisation cap and a reverse auction for altruistic purposes. -
Falsified data – A node reports high fidelity while injecting noise to sabotage.
› Mitigation: random Bell challenges, automatic loss of stake. -
Global South asymmetry – Countries with no premium nodes pay more for every QKD bit.
› Mitigation: a cross-subsidy fund, 2 % of all NRU transactions to install repeaters in Africa and South America.
VII Coda
“To govern the noise is to govern the trust.”
The quantum commons is no green metaphor; it is a real thermodynamic budget.
If we regulate only the money and not the heat and the fidelity, we will end up with a quantum network as chaotic as the over-fished seas of the twentieth century.
CEP-25 offers a sketch: tax the entropy, redistribute the order and let the coming probabilistic economy grow without collapsing its own foundation.