Science – Page 153 – Investment Policy

Beyond Gate Counts: Modeling the true Cost of Quantum Error Correction

12.11.2025 by Ray Dalio

A new cost model, FLASQ, offers a more realistic assessment of resource requirements for early fault-tolerant quantum algorithms.

Mapping Quantum Network Losses with Capacity Limits

12.11.2025 by Ray Dalio

$The network’s fidelity degrades predictably with increasing channel error, transitioning from an ideal, noise-free state—indicated by the baseline—to scenarios where all channels experience loss or bit-flip errors, with the most significant performance decline occurring when $QC_3QC_{3}$ exhibits both 30% loss and 30% bit-flip rates, demonstrating a compounding effect of these disturbances.$

A novel technique leverages network capacity regions to pinpoint loss probabilities, even amidst noisy channel conditions.

Verifying Quantum States with a Minimal Measurement Burden

12.11.2025 by Ray Dalio

The protocol operates by partitioning a global quantum system, discarding select subsystems, and certifying the remaining components—leaving a single component for further analysis—a strategy designed to navigate adversarial proofs through selective measurement and focused computation.

A new protocol efficiently certifies complex quantum states using only a small number of single-qubit Pauli measurements.

Unlocking Quantum Speedup: A New Way to Measure Coherence

11.11.2025 by Ray Dalio

$The efficacy of a generalized Bernstein-Vazirani algorithm hinges on maintaining quantum coherence—specifically, both state coherence, representing the preservation of superposition, and operator coherence, dictating the fidelity of quantum gate operations—as diminished coherence directly impacts the algorithm’s success probability, a relationship explored through quantifying the coherence fraction.$

Researchers quantify coherence in quantum algorithms, revealing its impact on performance with the Bernstein-Vazirani algorithm.

Encoding Quantum Data with Squeezed Light

11.11.2025 by Ray Dalio

A new approach to protecting quantum information leverages the unique properties of squeezed vacuum states.

Squeezing More Logic from Qubits

11.11.2025 by Ray Dalio

$The attempted suppression of hook error propagation within a densely packed surface code—achieved through meticulous gate scheduling—reveals an inherent limitation: even localized regions susceptible to logical-direction error propagation ($ \rightarrow $), despite representing only a fraction of the total system, foreshadow the inevitable emergence of systemic failure as the code scales.$

New techniques dramatically reduce the physical qubit overhead for fault-tolerant quantum computing with surface codes.

Encoding Logic with Quantum Error Correction

11.11.2025 by Ray Dalio

A new approach utilizes high-rate quantum LDPC codes to enable efficient, addressable gate-based computation.

Quantum Computing’s Flexible Future: ReQISC Redefines Control

11.11.2025 by Ray Dalio

ReQISC establishes a system for engineering arbitrary SU(4) gates through a time-optimal microarchitecture and a three-stage compilation framework, ultimately expressing this functionality via the {Can, U3} gate set—a foundational step towards programmable quantum computation.

A new full-stack framework promises to optimize quantum computations by tightly integrating hardware and software design.

Beyond Qubits: Encoding More Information in Quantum Systems

11.11.2025 by Ray Dalio

A logical qudit encoding—as demonstrated by the required Hilbert space—offers a potentially more efficient pathway to fault-tolerant quantum computation compared to conventional methods mapping information onto multiple logical qubits, a benefit that scales with qudit dimension and codeword distance.

A new approach to quantum error correction leverages ‘qudits’ – quantum units beyond simple 0 or 1 – to dramatically improve resource efficiency.

Shielding Quantum Signals from Noise

11.11.2025 by Ray Dalio

A new approach to quantum error correction promises to safeguard fragile quantum information from both thermal and environmental disturbances.