Forgetting feels like a failure of attention, but physics treats it as a fundamental process with a measurable price. At the smallest scales, erasing information is not free, it consumes energy and reshapes the microscopic state of the world, and that same logic is starting to reshape how I think about why memories fade in the brain.
By tracing how quantum systems store and delete information, researchers are uncovering rules that seem to rhyme with the way human memory works, from the cost of “letting go” of a thought to the way networks of neurons behave like entangled particles. The result is a new, more physical story about why we forget, one that links the warmth of a living brain to the cold mathematics of quantum theory.
The hidden cost of erasing a memory
In classical physics, the idea that forgetting has a price is captured by Landauer’s principle, which says that every time a bit of information is irreversibly deleted, a minimum amount of heat must be released into the environment. At the quantum level, that rule still holds, but it becomes more intricate, because information is no longer just a simple 0 or 1, it is encoded in delicate superpositions and correlations that can be spread across many particles. When I think about a memory being overwritten in the brain, I now picture not just neurons going quiet, but a physical reset that must push entropy somewhere else.
Researchers working on The quantum physics of forgetting information describe how Deletion in a quantum system is constrained by Landauer’s insight that erasing information, even at this microscopic scale, costs energy and increases disorder. In their analysis, the act of forgetting is not a vague metaphor, it is a thermodynamic operation that must be paid for in heat, and that framing makes it easier to see human memory as part of the same continuum, with every lost phone number or faded face tied, in principle, to a physical transaction in the tissue of the brain.
From Landauer to living brains
Landauer’s principle was originally formulated for idealized computing devices, but its logic is hard to ignore when I look at a biological organ that runs as hot and power hungry as the human brain. Neurons are constantly updating their internal states, strengthening some synapses and weakening others, and each of those updates is, in effect, a choice about which patterns of activity to preserve and which to erase. If erasing information in a quantum device must generate heat, it is reasonable to see the brain’s 20 watts of continuous power use as the macroscopic shadow of countless microscopic acts of forgetting, even if the exact accounting remains Unverified based on available sources.
Work on The Quantum Physics of Forgetting Information emphasizes that Deletion in quantum systems is not optional housekeeping but a process that must obey Landauer’s bound, and that perspective invites a provocative analogy with synaptic pruning and memory decay in neural tissue. When a network of neurons lets go of an old association so that it can learn a new one, it is effectively performing a reset on part of its information store, and the thermodynamic cost of that reset is paid in the chemical and electrical work needed to remodel synapses and maintain the brain’s temperature.
Measuring the “quantum price” of forgetting
For decades, Landauer’s principle was more of a theoretical limit than a laboratory measurement, especially in complex quantum systems where information is smeared across many degrees of freedom. That changed when Researchers at Wien and FU Berlin managed to track what happens as quantum information is deliberately erased, watching how energy and entropy flow into the surroundings as a system is forced into a standard reference state. Their experiments turned the abstract idea of a cost of forgetting into something that could be plotted on a graph and compared with theory.
In these studies, the team showed that when quantum information is deleted, the system must export both energy and disorder to its environment, a result described as the Quantum Price of Forgetting. For the first time, they could see Landauer’s limit at work in a regime where particles are entangled and subject to quantum statistics, confirming that even in this exotic setting, Deletion is inseparable from heat. When I map that insight back onto the brain, it suggests that every act of neural “reset,” from dampening a fear response to overwriting a childhood memory, must be grounded in similar bookkeeping, with the cost paid in metabolic fuel and microscopic noise.
Why quantum devices need to forget too
It is tempting to imagine a perfect quantum computer as a machine that never forgets, one that keeps every qubit in a pristine superposition until the final answer is read out. In practice, the story is more complicated, because useful algorithms often need to discard intermediate information so that the device does not drown in its own complexity. Forgetting, in this context, is not a bug but a feature, a way to keep the computational “maze” navigable so that the system does not lose track of how to get from input to output.
Analyses of quantum architectures note that, just like in everyday life, there are moments when a processor benefits from the ability to let go of partial results, a point highlighted in discussions of how However, quantum computing may need both remembering and forgetting to function. If every entangled state had to be preserved forever, the device would become unmanageable, much like a person who never discards any experience and ends up overwhelmed. The same Landauer limits that govern Deletion in these machines remind designers that each reset has a thermodynamic cost, so algorithms must be crafted to forget strategically, not wastefully.
Algorithms, memory, and the power of selective loss
When I look at how quantum algorithms are built, I see a kind of choreography of remembering and erasing, where information is created, spread across qubits, and then carefully uncomputed so that only the desired answer remains. This process is not just about speed, it is about controlling where entropy goes, because every irreversible step risks dumping heat into the hardware and degrading fragile quantum states. In that sense, the “power of forgetting” is really the power to decide which parts of a computation can be safely discarded without losing the essence of the problem.
Talks on Quantum algorithms and the power of forgetting describe how an algorithm can be designed so that unnecessary information is uncomputed or reset in a way that respects quantum coherence, a task that requires the kind of care that Ameen Shah and other researchers bring to the field. The lesson for human memory is striking: just as a quantum routine must forget intermediate steps to stay efficient, our own cognitive systems seem to benefit from pruning details that no longer serve a purpose, preserving only the patterns that help us navigate the world.
Distributed storage and the brain’s entangled feel
Neuroscience has steadily moved away from the idea of a single “memory center” and toward a picture in which experiences are stored across widely distributed networks of neurons. That shift mirrors, in a loose but suggestive way, the way quantum information can be encoded in entangled states that have no single, local carrier. When I recall a childhood street or the interior of a 2015 Toyota Corolla, the experience seems to arise from a coordinated pattern across the cortex, not from a single labeled file that can be opened or closed.
One analysis of Memory and Quantum Entanglement describes the brain as a kind of Distributed Storage system and urges readers to Forget the idea of a solitary memory node, emphasizing instead that Memories emerge from the interaction of many parts. In this view, forgetting is not simply the deletion of a single record, it is a change in the global pattern, a reweighting of connections that alters how the whole network resonates. That is very close to how entangled quantum systems behave when one part is disturbed, the entire state is reshaped, and information that once seemed accessible can no longer be cleanly extracted.
Jun, Wien, and the physics of real-world forgetting
The recent wave of work on the physics of forgetting is not happening in isolation, it is anchored in specific laboratories and collaborations that are trying to turn abstract theory into practical insight. Teams at TU Wien, working with partners in Berlin, have been particularly active in pushing these ideas forward, from conceptual analyses of Landauer’s bound in quantum regimes to experiments that track the actual flow of heat during Deletion. When I read their reports, the names and places, including Jun and Wien and FU Berlin, serve as a reminder that this is not just philosophy, it is bench science with concrete setups and measurements.
In one account of The Quantum Physics of Forgetting Information, researchers at TU Wien describe how they engineered quantum systems whose information content could be precisely controlled, then forced those systems through Deletion protocols that allowed them to test Landauer’s predictions. A related report on The Quantum Physics of Forgetting Information stresses that there is no measuring device that can access information without disturbing it, a point that becomes crucial when designing quantum technologies that must balance the need to read out results with the need to preserve coherence. For anyone thinking about human memory, that tension has a familiar ring, every attempt to retrieve a memory risks changing it, and every act of forgetting reshapes the landscape of what can be recalled.
What quantum forgetting suggests about our own minds
Putting these threads together, I find it hard to see forgetting as a simple flaw in human cognition. If physics insists that erasing information always has a cost, and if the most advanced quantum devices must forget strategically to function at all, then the brain’s tendency to let memories fade starts to look like a feature that keeps the system stable and efficient. The same thermodynamic pressures that shape Deletion in a lab experiment are, in a broad sense, at work in a warm, wet organ that has to juggle survival, learning, and limited energy.
Reports that describe For the first time, they have measured how a quantum system pays for forgetting, and that these scientists at TU Wien must account for both energy and entropy when they reset information, give a concrete backbone to this intuition. If even an idealized quantum device cannot escape the physics of forgetting, it would be surprising if a biological brain, constrained by blood flow, temperature, and molecular noise, could somehow store everything forever without consequence. Forgetting, in this light, is not a moral failing or a personal weakness, it is the mind’s way of staying within the bounds that the universe sets for any information processing system.
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