YC
John Preskill on Quantum Computing
@ Y Combinator
05/16/18
Takeaways
JP
John Preskill
05/16/18
@ Y Combinator
The idea that a quantum computer would be powerful was emphasized over 30 years ago by Richard Feynman, who believed that nature is quantum mechanical and that simulating nature should also be quantum mechanical.
JP
John Preskill
05/16/18
@ Y Combinator
Feynman proposed the concept of a universal quantum simulator, which we now refer to as a quantum computer, to simulate quantum systems more effectively than classical computers.
JP
John Preskill
05/16/18
@ Y Combinator
Peter Shor's suggestion that quantum computers could solve problems related to numbers, like finding the prime factors of large integers, sparked significant excitement due to its implications for cryptography.
JP
John Preskill
05/16/18
@ Y Combinator
In the mid-90s, we developed quantum error correction theory, which encodes quantum states in a way that protects them from environmental interactions, ensuring they remain robust.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum entanglement is a key property that allows information to be stored in the correlations between parts of a quantum system, making it difficult to access that information by examining individual parts.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum error correction takes advantage of entanglement to protect information from environmental disturbances, ensuring that the environment cannot learn anything about the protected information.
JP
John Preskill
05/16/18
@ Y Combinator
Grover's algorithm speeds up exhaustive searches through many possibilities, allowing quantum computers to handle larger problems more efficiently than classical computers.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum computers will likely excel in understanding and inventing new materials and chemical compounds, which are fundamentally quantum physics problems.
JP
John Preskill
05/16/18
@ Y Combinator
The practical impact of quantum computing will likely be seen in better methods for simulating quantum systems, which classical computers struggle to solve effectively.
JP
John Preskill
05/16/18
@ Y Combinator
Improving the reliability of quantum gates and reducing error rates will be crucial for scaling quantum computers and enabling them to solve more complex problems.
JP
John Preskill
05/16/18
@ Y Combinator
Microsoft is pursuing topological quantum computing, aiming to create qubits that can be controlled much better than current technologies, although it's still in the early stages of development. Scaling quantum technologies is challenging due to control engineering and other factors.
JP
John Preskill
05/16/18
@ Y Combinator
The coherence time of a qubit, which indicates how long it can interact with the outside world, has improved significantly, increasing about tenfold every three years over the past 15 years.
JP
John Preskill
05/16/18
@ Y Combinator
To continue this progress in quantum computing, we need better materials, fabrication, and control methods, particularly using microwave circuitry.
JP
John Preskill
05/16/18
@ Y Combinator
The key to effective quantum computing is ensuring qubits interact as desired, rather than just focusing on increasing coherence times.
JP
John Preskill
05/16/18
@ Y Combinator
Superconducting circuits and trapped ions are currently the most advanced technologies in quantum computing, with superconducting circuits likely to lead in the next five to ten years.
JP
John Preskill
05/16/18
@ Y Combinator
While superconducting circuits are faster than trapped ions, electron spins in silicon could potentially surpass them in the long term due to easier integration with existing technology.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum computers pose a risk to current encryption schemes, particularly public key cryptography, which relies on the difficulty of certain computational problems.
JP
John Preskill
05/16/18
@ Y Combinator
To protect privacy in a quantum computing era, we need to develop new cryptographic protocols that are resistant to quantum attacks, as well as explore quantum communication for secure information transfer.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum key distribution allows for secure communication by ensuring that any eavesdropping will disturb the quantum state, alerting the parties involved.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum systems can be used for improved sensing, potentially achieving higher sensitivity and spatial resolution than existing technologies, with applications in biology and medicine.
JP
John Preskill
05/16/18
@ Y Combinator
The entanglement frontier in quantum physics research will focus on scaling quantum systems to larger complexities, which could lead to new discoveries and insights into fundamental physics.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum error correction may play a crucial role in understanding the geometry of space-time, suggesting that entanglement is fundamental to the structure of the universe.
JP
John Preskill
05/16/18
@ Y Combinator
One misconception about quantum computing is that people often say quantum computers are powerful because they can superpose states, allowing them to perform many computations at once. However, this is misleading because ultimately, you need to make a measurement to read out the result, which limits the information you can obtain from those computations.
JP
John Preskill
05/16/18
@ Y Combinator
The key to making quantum algorithms work lies in the concept of interference, where the wrong answers cancel each other out, enhancing the correct answer. Designing a quantum algorithm to achieve this interference is not automatic; it requires careful planning.
JP
John Preskill
05/16/18
@ Y Combinator
To take advantage of quantum interference, measurements must be delayed. If you measure too early, the superposition is lost, resulting in a definite outcome that does not reflect the benefits of quantum computation.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum computing is fundamentally different from classical computing, and if you can determine which computational path was taken, you lose the speed advantage that quantum computing offers. It's essential to sum all possible computations without knowing which path was followed to leverage quantum mechanics effectively.
JP
John Preskill
05/16/18
@ Y Combinator
STEM education should focus on teaching the general population to reason effectively and critically evaluate arguments, rather than just training a technical workforce. This approach will help individuals make informed decisions in a democratic society.
JP
John Preskill
05/16/18
@ Y Combinator
Having scientifically trained individuals in government can positively influence science and educational policy. Examples include physicists like Bill Foster and Rush Holt, who have made significant contributions during their time in Congress.
JP
John Preskill
05/16/18
@ Y Combinator
The Department of Energy under the Obama administration facilitated technical innovation by supporting startups focused on improving battery technology and solar power, which could benefit future generations.
JP
John Preskill
05/16/18
@ Y Combinator
Quantum startups are increasingly concentrated in the Bay Area due to the presence of the tech industry and investors interested in financing innovative technical ventures. This trend may continue as the field develops.
JP
John Preskill
05/16/18
@ Y Combinator
When forming a team for a quantum computing startup, it's crucial to have individuals with diverse expertise. Effective communication across different areas of knowledge, such as software and control engineering, is vital for success in this complex field.
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John Preskill
05/16/18
@ Y Combinator
Teaching is a powerful way to deepen your understanding of a subject. By trying to explain complex topics to others, you can gain new insights and clarify your own knowledge, which is beneficial for both the teacher and the students.
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John Preskill
05/16/18
@ Y Combinator
Leonard Susskind is a highly regarded communicator in physics, known for his ability to make complex topics accessible. His lectures and the series 'Theoretical Minimum' provide a gentle introduction to various physics concepts, including quantum physics.