Quantum Tech & Time
Looking into the morning sky, it occurred to me I was looking at the Sun as it was in the past. What do I mean? And what does time have do with quantum technology?
You're Looking at the Old Sun
The average distance from the Earth to the Sun is approximately 149.6 million kilometers (or 149,600,000 km). The speed of light is about 299,792 kilometers per second (km/s). To calculate the time it takes for light to travel from the Sun to the Earth, we divide the distance by the speed of light:
Time = Distance/Speed of light = 149,600,000 km/299,792 km/s
The time it takes for light to travel from the Sun to the Earth is approximately 499 seconds, or about 8 minutes and 19 seconds.
Whenever you look at the Sun, it's the Sun from 8 minutes ago. The relationship between distance, speed and time.
Image source: Brian Lenahan
Quantum & Time
The relationship between quantum technologies and time is deep and multifaceted, touching on areas such as quantum mechanics, time measurement, timekeeping, and even time as a concept within physical theories. Here's how quantum technologies are related to time in key areas:
1. Quantum Clocks:
Quantum technologies have revolutionized timekeeping through the development of quantum clocks, especially atomic clocks. These are the most precise timekeepers in the world, based on quantum phenomena such as the energy transitions of atoms.
Atomic Clocks: These clocks measure the oscillations of electrons between energy levels in an atom (usually cesium or strontium) and use this as a reference for time. Atomic clocks are so precise that they lose only about 1 second every millions of years.
Quantum Effects: The quantum nature of atoms and their energy levels is key to this precision. The time it takes for an electron to move between energy levels is highly stable and can be measured very accurately.
Impact on Timekeeping: These quantum clocks are used for global time standards, GPS, and even to test fundamental theories about time itself.
2. Quantum Entanglement and Time:
Quantum entanglement creates intriguing relationships across time. Entangled particles exhibit correlations that remain even if they are separated by vast distances, seemingly defying classical notions of causality and time.
Spooky Action at a Distance: Einstein famously referred to this phenomenon as "spooky action at a distance." When one entangled particle is measured, its state is instantly known, and so is the state of its entangled partner, even if they are far apart. This happens without any delay that classical communication (which is limited by the speed of light) would suggest.
Causal Paradoxes?: Entanglement raises questions about time and causality, as it seems to challenge the conventional "arrow of time" and raises possibilities for experiments that could explore time-like and space-like separations in quantum systems.
3. Quantum Computing and Time-Efficient Algorithms:
Quantum computing promises to drastically reduce the time it takes to solve certain problems compared to classical computers.
Time Complexity: In classical computing, the time required to solve some problems grows exponentially with the size of the input (e.g., factoring large numbers, simulating quantum systems). Quantum computers, leveraging quantum superposition and entanglement, could solve these problems in polynomial time (e.g., Shor's algorithm for factoring large numbers).
Speedups: This is significant for tasks such as cryptography, optimization, and simulating complex physical systems where classical computation would take an unfeasibly long time.
4. Time in Quantum Mechanics:
Time itself is treated differently in quantum mechanics compared to classical physics. In quantum theory:
Time Evolution: The evolution of quantum systems over time is governed by the Schrödinger equation. Time is a parameter that dictates how the wavefunction, which describes the state of a quantum system, changes.
Uncertainty Principle: Quantum systems also have an uncertainty relation involving time and energy, akin to the Heisenberg uncertainty principle that applies to position and momentum. There is a trade-off between how precisely energy and time can be measured.
Quantum Gravity and Time: One of the unsolved questions in physics is how time behaves in a theory that unites quantum mechanics with general relativity (quantum gravity). In general relativity, time is affected by gravity (e.g., time slows near massive objects), but quantum mechanics treats time more like a background parameter.
5. Quantum Metrology:
Quantum technologies also enable better measurement of time intervals, down to incredibly small scales, through quantum metrology.
Precision Timing: Quantum sensors can measure extremely small time differences, helping in applications like gravitational wave detection, where incredibly tiny time delays in the arrival of light from distant astronomical events need to be measured with extreme precision.
6. Time Crystals:
In recent years, the discovery of time crystals has provided a new quantum state of matter that is closely tied to time. A time crystal is a system that exhibits periodic motion without consuming energy, thus appearing to break the conventional symmetry of time.
Perpetual Motion: This doesn’t violate thermodynamics, but time crystals are fascinating because they exhibit motion in a time-like pattern, even in their ground state (the state of lowest energy), and could provide insights into non-equilibrium quantum systems.
Summary
Quantum technologies both rely on and deepen our understanding of time. Whether through ultra-precise quantum clocks, the study of entanglement’s defiance of classical causality, quantum computation’s speedups, or the exploration of quantum mechanical principles, these technologies are intertwined with the nature of time at its most fundamental levels. Quantum physics continues to challenge and refine our understanding of time, pushing the boundaries of science and technology.
Brian Lenahan is founder and chair of the Quantum Strategy Institute, author of seven Amazon published books on quantum technologies and artificial intelligence. Brian’s focus on the practical side of technology ensures you will get the guidance and inspiration you need to gain value from quantum now and into the future. Brian does not purport to be an expert in each field or subfield for which he provides science communication.
Brian’s books are available on Amazon. Quantum Strategy for Business course is available on the QURECA platform.
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