What is the hardware for quantum gates?

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Discussion Overview

The discussion centers around the hardware implementations of quantum gates, exploring the practical aspects of how theoretical concepts are realized in physical systems. Participants seek to understand the relationship between the abstract mathematical representation of gates and their physical counterparts in quantum computing.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses a desire for a basic understanding of the practical hardware behind quantum gates, contrasting it with theoretical knowledge of matrices and linear operators.
  • Another participant notes the abstract nature of a "gate," emphasizing that its implementation relies on various hardware types and control mechanisms.
  • It is mentioned that gates are typically realized through adjustments of parameters using control knobs like microwave fields, laser light, and magnetic or electric fields.
  • A specific example is provided where a microwave pulse is used to implement a gate for spin-based and superconductor-based qubits.
  • Linear optics is suggested as a method for developing quantum gates, with a reference to a document discussing Hadamard transformations using beamsplitters.

Areas of Agreement / Disagreement

Participants appear to agree on the abstract nature of quantum gates and the necessity of hardware for their implementation. However, there is no consensus on specific hardware details or methods, indicating that multiple views and approaches remain in the discussion.

Contextual Notes

Some limitations include vague statements regarding the use of variable magnetic fields and the lack of specific examples or detailed explanations of hardware implementations. The discussion does not resolve the complexities involved in realizing quantum gates in practice.

Who May Find This Useful

This discussion may be of interest to individuals exploring the intersection of theoretical quantum mechanics and practical quantum computing hardware, particularly those seeking foundational knowledge in quantum gate implementations.

nomadreid
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I have lots of materials on the theory of quantum gates in terms of matrices, linear operators, and so forth. However, I would like to gain a basic understanding of how these matrices are achieved in practice. The difference is between knowing that a transistor acts as a switching or amplifying device, and knowing that this is achieved by making a PNP or NPN semiconductor sandwich etc. Web sites which explain it in non-specialist terms (I view hardware as a sort of necessary evil for the theory to be applicable) are welcome, as long as they do not send me to a site that requires paid access. All that I have been able to glean from the Internet is that crystals are often used. I don't need too much detail, but more detail than that... Thanks in advance.
 
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Only some rather vague statements about using variable magnetic fields, but nothing specific.
 
A "gate" is an abstract mathematical concept. How you actually implement the operation described by a sequence of gates depends entirely on what type of hardware you use.
The "gate" itself is very rarely a physical "thing" but rather a sequence of changes of a some set of parameters.That is, typically, you end up using a few different "control knobs" to implement a gate (microwave fields, laser light, magnetic or electric fields etc) , by adjusting these as a function of timeyou can implement a gate.

The simplest example of a gate would be a single pulse of some sort. For both spin-based and superconductor based qubits this will be a microwave pulse with a specific frequency, amplitude and length.

Note that all manipulation used in NMR/MRI would in the language of QC be described as "gate operations".
 
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Hi, nomadreid

The linear optic can be used to develop quantum gate. For example, http://copilot.caltech.edu/documents/278-weihs_zeillinger_photon_statistics_at_beamsplitters_qip.pdf can be used for Hadamard transformation.

/Patrick
 
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