Quantum Memory Erasure Achieves Exclusive Control, Linking Entanglement to Minimal Energetic Cost

Erasing information requires energy, a principle with profound implications for future technologies, and scientists are now exploring ways to minimise this cost. Mir Alimuddin, Nathan Shettell, and Raja Yehia, working with colleagues at ICFO-Institut de Ciencies Fotoniques and the Centre for Quantum Technologies, demonstrate a new approach to information erasure that allows exclusive control over the process. Their research introduces ‘assisted erasure’, where connections with another system reduce the energy needed to reset memory, and crucially, establishes that only an authorised party can achieve this minimal cost. This work elevates erasure from a necessary constraint to a fundamental operational tool, quantifying secure memory control and guaranteeing protection against unauthorised access, a significant step towards truly secure information processing.

Device-Independent Quantum Memory Protection Schemes

The research explores methods for protecting quantum information stored in memory from corruption or theft, focusing on scenarios where the level of trust placed in the devices used by those protecting the information varies. Scientists investigate both device-dependent security, where devices are largely trusted, and semi-device-independent security, where trust is limited but still achievable through specific protocols. Key to this work is the concept of assisted erasure, where reducing the energetic cost of resetting memory requires a connection with another system, and establishing exclusivity, ensuring only authorized parties can achieve this minimal cost. The team demonstrates that verification routines, where Bob checks the memory’s state, act as critical safeguards against irreversible damage caused by an adversary. Random dephasing, a technique that randomizes the quantum state, further enhances security in the semi-device-independent approach. The results show that Eve, an adversary, cannot corrupt the memory beyond Bob’s control unless Bob intentionally erases it, establishing a robust framework for quantum memory protection.,.

Entanglement Enables Low-Energy Information Erasure

This study pioneers a method for erasing information with minimal energy expenditure, building upon Landauer’s principle which links information loss to work. Researchers investigated ‘assisted erasure’, where correlations with a remote system reduce the energetic cost of resetting memory, establishing exclusive control as central, only a designated party should achieve minimal cost, while an adversary cannot. The team demonstrated that entanglement of formation precisely characterizes this exclusivity, establishing entanglement as the decisive resource for efficient erasure. To achieve this, scientists developed a semi-device-independent erasure protocol utilizing random dephasing, a technique where quantum coherence is intentionally destroyed, combined with conditional operations performed on the memory.

Bob, the memory holder, first chooses one of two dephasing bases and decoheres his memory, while Alice then applies a corresponding operation, followed by Bob’s conditional erasure. A crucial verification step involves coupling the system to a Szilard-type engine, a device that converts information into work, demonstrating successful erasure and reversibility. The team rigorously tested the protocol’s security by considering scenarios where an adversary, Eve, attempts to mimic Alice’s actions, proving that Eve can perfectly match the erasure cost achieved by Alice only if the system behaves classically.,.

Entanglement Enables Exclusive Quantum Erasure

Scientists have demonstrated a groundbreaking method for erasing quantum information with significantly reduced energetic cost, building upon Landauer’s principle which establishes a minimum work requirement for information erasure. The research establishes that assisted erasure, where correlations with a remote system lower the work needed to reset a memory, can be achieved with exclusive control, meaning only a designated party can achieve the minimal cost while any adversary fails. Experiments reveal that entanglement of formation precisely characterizes this exclusivity, establishing entanglement as the decisive thermodynamic resource for efficient erasure. The team developed an operational erasure protocol based on random dephasing and conditional operations, achieving a reduction in work cost when a trusted helper (Alice) assists in erasing information from Bob’s memory. Measurements confirm that Alice outperforms an adversary (Eve) in assisted erasure precisely when her entanglement with Bob exceeds Eve’s, demonstrating a clear link between quantum correlations and thermodynamic advantage. The research establishes a baseline work cost directly related to the entropy of the memory, and shows how this cost can be lowered through the consumption of initial correlations between systems.,.

Exclusive Erasure Control Via Entanglement Resources

This research establishes exclusive control of erasure as a fundamental operational principle in information processing, moving beyond its traditional understanding as a mere thermodynamic cost. Scientists demonstrate that reducing the energetic cost of resetting memory requires correlations with a remote system, and crucially, that only a designated party should achieve minimal cost while any adversary fails. In scenarios where the devices involved are well-characterized, the research identifies entanglement of formation as the key resource determining exclusivity; a greater degree of entanglement between the designated helper and the memory holder guarantees exclusive control. Furthermore, the team developed a protocol for one-sided device-independent scenarios, where trust is limited to the memory holder’s device, based on random dephasing and conditional operations.

This protocol reveals that exclusivity is governed by an entropic uncertainty threshold, meaning that achieving exclusive control requires surpassing a specific bound on information uncertainty. Importantly, the framework guarantees that even with malicious intervention, any external interaction can be treated as either a detected failure or an effective honest run, preventing further loss of information beyond a declared work budget. This elevates erasure to an active tool for access control, where the ability to erase information itself becomes a protected resource. The authors highlight the potential for future work to explore fully device-independent scenarios, and to extend the framework to allow quantum messages, broadening the range of states supporting exclusive thermodynamic control.