YC
Simon Benjamin on Architectures for Quantum Computing
@ Y Combinator
05/26/18
Takeaways
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Simon Benjamin
05/26/18
@ Y Combinator
Quantum computing has gained significant attention recently because it's starting to work in labs, reaching a point where it can perform tasks that classical computers cannot.
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Simon Benjamin
05/26/18
@ Y Combinator
In the last three years, there's been a surge of interest from companies wanting to collaborate with academics on quantum computing research, marking a significant shift from previous years when companies were hesitant to invest.
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Simon Benjamin
05/26/18
@ Y Combinator
Qubits, the building blocks of quantum technology, are inherently unstable and tend to collapse to a single state, making them difficult to control compared to classical bits.
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Simon Benjamin
05/26/18
@ Y Combinator
Achieving high fidelity in qubit operations is crucial; the Oxford team has reached a fidelity of 99.9%, which is essential for reliable quantum computing operations.
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Simon Benjamin
05/26/18
@ Y Combinator
To manage errors in quantum computing, researchers use multiple physical qubits to represent a single logical qubit, allowing for error correction without directly observing the qubits.
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Simon Benjamin
05/26/18
@ Y Combinator
The concept of using ancilla qubits for error detection allows researchers to check for errors in quantum computations without disturbing the main qubits, which is a significant breakthrough in quantum error correction.
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Simon Benjamin
05/26/18
@ Y Combinator
The threshold for effective quantum computing has improved to around 99% fidelity, meaning that if a quantum computer operates correctly 99% of the time, it can effectively manage errors and perform complex calculations.
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Simon Benjamin
05/26/18
@ Y Combinator
Topological codes, particularly the higher surface code, are promising approaches for building quantum computers due to their simpler architecture, allowing qubits to be arranged in a grid and only requiring local interactions.
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Simon Benjamin
05/26/18
@ Y Combinator
The ability to lay out qubits in a grid simplifies the design of quantum computers, as it aligns with the short-range interactions typical in quantum physics, making it easier to achieve reliable operations. Topological codes allow qubits to be arranged in a grid, enabling them to communicate with immediate neighbors without the need for extensive movement, which simplifies operations significantly.
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Simon Benjamin
05/26/18
@ Y Combinator
Network approaches to quantum computing enable any qubit to link with any other qubit, enhancing connectivity and power, despite the increased risk of errors if not managed correctly.
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Simon Benjamin
05/26/18
@ Y Combinator
The ion trap method, which uses individual atoms as qubits, is a leading approach in quantum computing due to its ability to maintain quantum states effectively by isolating atoms from their surroundings.
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Simon Benjamin
05/26/18
@ Y Combinator
In quantum physics, the thought experiment of Schrödinger's cat illustrates the concept of superposition, where a quantum system can exist in multiple states simultaneously until measured.
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Simon Benjamin
05/26/18
@ Y Combinator
In quantum computing, the challenge is to keep qubits isolated to prevent decoherence, which can be achieved through various techniques, including using vacuum chambers and ion traps.
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Simon Benjamin
05/26/18
@ Y Combinator
Maintaining a vacuum is essential in quantum computing to prevent atoms from interacting with external particles, which could disrupt their quantum states.
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Simon Benjamin
05/26/18
@ Y Combinator
Ion traps allow for precise manipulation of charged atoms in a vacuum, enabling the creation of stable qubits that can perform complex calculations without interference from the environment.
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Simon Benjamin
05/26/18
@ Y Combinator
The ion trap technology is not only effective but also relatively straightforward, relying on basic principles of physics to manipulate atoms for quantum computing purposes. The system successfully isolates natural quantum units from the rest of the universe, allowing them to maintain delicate quantum states for extended periods and enabling high-level control and interaction between them, making them the gold standard of qubits.
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Simon Benjamin
05/26/18
@ Y Combinator
The decoherence time, which is the duration a qubit can maintain its quantum state, is crucial for quantum computing, with ion traps achieving significantly longer coherence times compared to other methods.
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Simon Benjamin
05/26/18
@ Y Combinator
The ability to perform hundreds of thousands of operations per second in quantum computing means that even a short decoherence time can be sufficient for many calculations.
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Simon Benjamin
05/26/18
@ Y Combinator
Superconducting qubits are the primary approach used by companies like Google, IBM, and Intel, each with its own strengths and weaknesses compared to other quantum computing methods.
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Simon Benjamin
05/26/18
@ Y Combinator
The challenge in quantum computing lies in scaling; while achieving high fidelity with a small number of qubits is possible, creating a robust system that consistently performs well with a larger number of qubits is a significant engineering problem.
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Simon Benjamin
05/26/18
@ Y Combinator
Quantum supremacy refers to the point where a quantum computer can perform tasks that classical computers cannot efficiently replicate, but it is often seen as a hyped term that may not accurately reflect the practical implications of quantum computing advancements.
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Simon Benjamin
05/26/18
@ Y Combinator
To be genuinely useful, a quantum computer needs to exceed 50 qubits, as tasks requiring fewer qubits can still be efficiently simulated by classical computers, making them less impactful.
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Simon Benjamin
05/26/18
@ Y Combinator
The gap between the theoretical usefulness of quantum computers at around 50 qubits and the practical requirements for tasks like code-breaking, which may need thousands of qubits, highlights the current limitations in quantum computing capabilities.
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Simon Benjamin
05/26/18
@ Y Combinator
Quantum-enabled discovery could revolutionize fields like drug discovery by allowing quantum computers to predict molecular behaviors, significantly speeding up the process of synthesizing complex molecules without relying on trial and error.
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Simon Benjamin
05/26/18
@ Y Combinator
The potential for quantum computers to simulate chemistry and material systems could lead to breakthroughs in various scientific fields, although the exact number of qubits required for these tasks remains uncertain.
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Simon Benjamin
05/26/18
@ Y Combinator
The approach to scalability in quantum computing involves creating small, efficient quantum modules that can be linked together, rather than trying to scale up a single large quantum computer, which presents numerous challenges.
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Simon Benjamin
05/26/18
@ Y Combinator
Using multiple links in quantum communication can improve the quality of information transfer, similar to how conventional technology compensates for weak signals by requesting data multiple times to ensure accuracy.
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Simon Benjamin
05/26/18
@ Y Combinator
To determine if a quantum computer can be modular, we need to assess whether we can achieve good quality entanglements between two modules, which would prove they are part of the same quantum state.
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Simon Benjamin
05/26/18
@ Y Combinator
If you can't achieve entanglement between the Alice module and the Bob module, your quantum machine will essentially remain a collection of separate units, unable to perform a unified quantum calculation.
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Simon Benjamin
05/26/18
@ Y Combinator
We can create qubits that are entangled at 90% quality, but we can store them practically forever, allowing us to enhance their quality through a process similar to improving a staticky communication channel.
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Simon Benjamin
05/26/18
@ Y Combinator
By sacrificing one low-quality Bell pair, we can boost the quality of another, effectively creating a better communication link between quantum modules.
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Simon Benjamin
05/26/18
@ Y Combinator
As long as the quantum modules have good memory and quality internal operations, we can take a poor quality link and enhance it to function as a high-quality link.
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Simon Benjamin
05/26/18
@ Y Combinator
We plan to build a modular quantum computer made of small quantum modules that, when linked, can work together to form a unified quantum state.
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Simon Benjamin
05/26/18
@ Y Combinator
The initial speed of our modular quantum computer will be limited by the connection rate between modules, but for small problems, the computation speed won't be a major concern.
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Simon Benjamin
05/26/18
@ Y Combinator
The first generation of our technology may be slower than other approaches, but it will offer higher fidelity and connectivity, making it suitable for different types of problems.
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Simon Benjamin
05/26/18
@ Y Combinator
The modular approach allows for scalability; once we establish a strong link between two modules, we can expand to many more without significant additional complexity.
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Simon Benjamin
05/26/18
@ Y Combinator
The timeline for building a modular quantum computer depends on interest and investment, but demonstrating two fully linked modules is an immediate goal for the next year.
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Simon Benjamin
05/26/18
@ Y Combinator
The quantum computing field is diversifying, and there are now opportunities for software engineers and systems engineers to contribute without needing deep quantum physics knowledge.