Long a "Holy Grail" of scientists and engineers, quantum computers that can be used in practical applications are steadily inching closer to becoming a reality.
Hours of research by our editors, distilled into minutes of clarity.
Unlike regular computers, where each bit is either 0 or 1, quantum computers use qubits, which can simultaneously be both—allowing for massive parallel processing power. Google’s quantum processor once solved a problem in seconds that would have taken a supercomputer 47 years.
Just as waves are extended objects whose heights change across space, quantum waves dictate that the probability of an object existing in different locations across space varies. Like water waves, the probability waves can combine, changing the heights—and therefore probabilities—in different locations.
From wooden machines to wearable tech, computers have changed a lot in appearance, but they all still perform the same essential tasks. Early computers were made of wood and metal—some were so big that they filled entire rooms just to solve simple math problems.
As computer parts shrink, transistors—tiny switches that control the path of electrical signals—become obsolete because electrons can quantum tunnel through switch barriers. This makes quantum computers, which take advantage of quantum effects, an enticing alternative.
Quantum entanglement occurs when two or more particles become linked, resulting in correlated properties. Scientists have ruled out hidden variables and have shown that these correlations depend on how and when measurements are made—not on faster-than-light communication.
Classical computers manipulate bits as either 0 or 1, but quantum computers use qubits to hold combinations of both, enabling new algorithms. This new approach could one day help with breakthroughs in medicine, chemistry, and AI.
Relying on electrons experiencing no friction across metal, these qubits require extremely low temperatures and behave like artificial atoms. The first superconducting qubit, invented in 1999, was large enough to be seen with the naked eye.
No winning qubit technology exists among photonic networks, superconducting circuits, spin qubits, neutral atoms, and trapped ions. Each has significant limitations and unique advantages, such as neutral-atom systems' ability to maintain quantum states for several minutes, far longer than the others.
Erwin Schrödinger's famous cat thought experiment illustrates how quantum objects can exist simultaneously in multiple states. This superposition allows electrons to behave as particles and waves, enabling chemical bonds and the function of modern electronics.
Recent advances in error suppression, mitigation, and correction are allowing quantum computers to perform practical tasks that challenge classical machines. IBM’s 2016 launch of its first cloud-accessible quantum computer attracted over 22,000 users in its first month alone.
Since the time our ancient human relatives began using stone tools to perform tasks, humans have harnessed scientific knowledge and new technologies to advance our ability to feed ourselves, increase our health, expand the boundaries of our knowledge, and much more. From artificial intelligence and quantum computing, to optimizing the human body in pursuit of a long and healthy life, and much more—learn about these topics and more with our smart-but-digestible overviews and expert-curated resources.