Thermodynamic and Quantum Constraints on Scalable Quantum Computing

In the paper's words

The central tension in scalable quantum computing lies between the exponential growth of quantum information density and the polynomial limits of cryogenic heat extraction. This thermodynamic bottleneck motivates an architectural inversion, where high-power control and readout electronics are offloaded to the 4 Kelvin stage to leverage its vastly greater cooling capacity. However, the physical viability of this paradigm is contingent upon qubits maintaining high-fidelity operation in this more energetic environment.

The abstract, verbatim, and its opening sentence is the claim. Every line below is quoted from the text.

Numbers it reports

1. The numerical analysis shows that by transitioning from standard amorphous dielectrics ($\tan\delta \approx 10^{-5}$) to state-of-the-art low-loss material systems ($\tan\delta \lt 10^{-7}$), the decoherence-limited single-qubit gate fidelity at 4 Kelvin can exceed 99.96%, becoming statistically indistinguishable from the ideal performance at 10 millikelvin.

   from A Consilience

2. In stark contrast, the pulse tube stage, operating at 4 Kelvin, offers a cooling budget roughly 20,000 times larger, often exceeding 1 watt.

   from 1.1 Scaling Asymmetry

3. Conversely, demanding operation at the absolute floor of 10 millikelvin imposes a severe penalty on the allowable heat dissipation.

   from 1.1 Scaling Asymmetry

4. If we consider a system performing $10^8$ measurements per second, the raw Landauer cost at 10 millikelvin is on the order of femtowatts.

   from 1.3 Landauer Limit

5. If we attempt to place this load at the 10 millikelvin stage, a single qubit controller would consume the entire cooling budget of the refrigerator (50 microwatts) hundreds of times over.

   from 1.5 Control Power Dissipation

6. However, at the 4 Kelvin stage, where the cooling power is approximately 1 watt, the budget can accommodate the control logic for hundreds or even thousands of qubits, provided the power per qubit is optimized.

   from 1.5 Control Power Dissipation

How it is done

1. of Modeling, Experiment, and Theory Author: Rowan Brad Quni-Gudzinas Contact: rowan.quni@outlook.com ORCID: 0009-0002-4317-5604 ISNI: 0000000526456062 URL: https://papers.qnfo.org/papers/thermodynamic-constraints-and-architectural-inversions-in-scalable-quantum-information-systems/ Date: 2025-12-19 Version: 2.0 Abstract : The central tension in scalable quantum computing lies between the exponential growth of quantum information density and the polynomial limits of cryogenic heat extraction.

   from A Consilience

2. This historical trajectory suggests that the “brute force” approach of building larger refrigerators is yielding diminishing returns.

   from 1.1 Scaling Asymmetry

3. This approach transforms the wiring problem from a global interconnect challenge to a local integration challenge.

   from 1.2 Wiring Bottleneck

4. The Landauer limit establishes a fundamental lower bound on the energy that must be dissipated as heat when a bit of information is erased or logically merged.

   from 1.3 Landauer Limit

What would falsify it

The paper's text states no explicit falsification criterion; the limits below are what it says about where the claim stops.

Where the claim stops

1. However, the physical viability of this paradigm is contingent upon qubits maintaining high-fidelity operation in this more energetic environment.

   from A Consilience

2. The cooling power of the mixing chamber, operating at approximately 10 millikelvin, is physically constrained to the microwatt regime, typically capping at 50 microwatts for standard commercial systems.

   from 1.1 Scaling Asymmetry

3. However, as system sizes expanded from single digits to hundreds of qubits in the early 2020s, the linear increase in control lines began to saturate the cooling budget.

   from 1.1 Scaling Asymmetry

Where to read

1. 1.0 Introduction3,192 words · 14 min
2. 2.0 Theoretical Framework1,035 words · 5 min
3. 3.0 Methodology517 words · 2 min
4. 4.0 Analysis563 words · 2 min
5. 5.0 Conclusion1,423 words · 6 min