Questions tagged [architecture]
For questions related to building of quantum computers and discussion of the hardware aspects.
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If the main challenges limiting quantum computing's abilities will be passed, will even video games be run on quantum computers?
I'm terribly sorry for my lack of knowledge in (quantum) computer architecture, I still need to learn a lot. But I'd like to know whether quantum computers can execute the same tasks (like running a ...
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Are indistinguishable bosons and fermions computationally equivalent to distinguishable qubits?
From the middle-late decades of the last century, many researchers such as Bennett, Benoif, Deutsch, Feynman, Manin, Wiesner, among others, had some intuition that qubits are computationally more ...
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Are there qudit systems and why they are not as popular?
Qudit is a $d$-level system that generalizes a qubit. From what I understood qudits are more resource efficient when it comes to spanning the state space. If $N$ is a dimension of a state space, then ...
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The world's first quantum integrated circuit at the atomic scale - How does this advance quantum computing as a whole?
I have a hobbyist/enthusiast understanding of Quantum Computing, having read a few books on the subject. I came across this new article and referenced Nature paper. I know a goal of quantum computing ...
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Gate times for photonic quantum computers
I am trying to understand the landscape of one- and two-qubit gate times for various quantum computing architectures. It is not so hard to find gate times for various gates such as Hadamard, CNOT and ...
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Are there any quantum standards already in development and accessible as draft documents?
Are there any quantum standards already in development and accessible as draft documents?
Any documents describing standardized way of describing and ensuring common meaning/interoperability, like e.g....
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Good review articles on microwave hardware for superconducting qubit quantum computing?
I am trying to find some review articles on the microwave hardware used in superconducting qubit quantum computing.
So far, most papers that I found seem to be high level overviews, e.g., Multilayer ...
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Questions on Definitions and Concepts Regarding Toric Codes
Currently, I reading the toric code section in the beginning of the paper Topological Quantum Memory. Here are a couple of sections that are somewhat confusing to me.
(1)
This quote below is under a ...
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A Particular Way of Erasing Ancilla Qubits
I am currently reading the paper Topological Quantum Memory by Dennis, Kitaev et. al. My main interest is to conceptually understand the idealized assumptions / requirements of a quantum computer ...
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What constitutes a quantum database?
Newb question, I know it's broad. I'm coming here for validated pointers, so I can know what to read. I have QT for CS (Yanofsky, Mannucci) and am reading about Shannon and Von Neumann entropy, but I'...
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What are the pros and cons of the most popular QC architectures?
I notice numerous companies and research groups around the world trying to build QC's with wildly different approaches. Intuitively, this suggests to me that QC is still very early in its maturation - ...
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Usefulness of having a cryogenic controller at 4K for transmons/spin qubits
There have been plenty of papers on the design of cryogenic control chips working at ~4K for qubit control and readout. These papers talk about how running coaxial cables from room temperature control ...
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Can we calculate the quantum volume of a classical computer?
The quantum volume is typically taken as a popular metric to determine the capability of a quantum computer to solve complex problems. Since the end goal is to develop quantum computers that can solve ...
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Are classical analogues of quantum computers using superposed waves possible? [duplicate]
The trick of quantum computing is to take the advantage of wave mechanics (superposition) and entanglement. This allows to perform parallel computations/manipulations with $2^n$ superposed waves for $...
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Is there any quantum gate that can change quantum hardware topology(architecture)?
I read about this paper
Hardware-aware Heuristic for the Qubit Mapping problem in the NISQ Era.
I wonder there is the only SWAP gate that can change the quantum hardware topology.
Is there any gates ...
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Solution for the "Input and Output theory" for circuit/cavity-QED Quantum Architecture [closed]
This question consists of the basic calculations which are often referred to as "trivial" in most references in circuit-QED. However, are not so trivial for anyone who starts fresh into the ...
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A distributed, scale-out quantum computing architecture?
Having been part of the mainframe, client-server, and now containers scale out architecture, I can observe the parallel and resemblance of today's quantum computers (massive) to that of the mainframe ...
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Is there a good reason to use T-count minimization for circuits executed on current IBM open quantum systems (real hardware)?
As far as I understood from a series of papers, minimizing the T-count in Clifford+T circuits is essential for fault-tolerant ...
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What determines the topology/connectedness of quantum computers?
Some quantum computers hold their qubits in a 2D array. I've even seen a 1D topology I think.
On IBM Q, you can see which qubits talk to which qubit. I would like to know what determines/limits the ...
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What is the executable opcode for Qiskit quantum hardware, as the quantum circuits or the transpiled/compiled QObj/ QASMQObj are assembly languages? [duplicate]
When we write a QASM code or build quantum circuit on Qiskit GUI, it converts it into QObj/QASMQObj (refering paper Qiskit Backend Specifications for OpenQASM and OpenPulse Experiments) or its ...
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What are the practical limitations of complementing quantum computations with memristors?
Considering the current state of research into quantum memristors, and the advantages/disadvantages of quantum and memristor driven computing architectures:
Quantum Memristors
Quantum Memristor ...
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How to build a quantum computer in your house?
As still quarantine is going on for some of us. I was wondering how to make a Quantum Computer in your garage. What may be the total cost for building one?
Was inspired by this youtube video.
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Why don't quantum computing scientists build two 50-qubit processors and connect them in parallel instead of building one 100-qubit processor?
Isn't it more scalable to build multiple processors of a lower qubit and connect them in parallel instead of building one processor of a higher qubit?
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Is quantum computing the most advanced computing technology we will ever have? [closed]
Is there already evidence today (e.g. basic theoretical research or even prototypes) on what the next technolgy will be/could be that is superior to quantum computers?
Or have we reached the "...
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Are all the IBM QX mapping bidirectional?
The connection between physical qubits of IBM devices are all bidirectional or there are some architectures that there existing some unidirectional connection?
I found that in IBM Quantum experience, ...
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What is the state of the art on Quantum Random Access Memories? [duplicate]
I realized that Quantum Random Access Memory (qRAM) was proposed to make quantum computers more similar to classical one. Currently quantum computers have very constrained memory, given only quantum ...
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Why IBM devices have the same number of qubit and the same architecture, but the error rates are different?
Here are two different IBM quantum online devices,
Both of them have the 5 qubits and the same architectures.
But why do they have different error rate?
What's the different between them?
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What are the general hardware components of a universal quantum gate computer?
Although the architecture of a quantum computer depends on the implemented qubit system, I still wonder what the general structure of hardware parts would be.
Evidently, a quantum computer isn't ...
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How many types of quantum computers are currently being researched? [duplicate]
I came across a "new" type of quantum computer - photonic quantum computing. Is this type of technology of interest here? You may read about an example here. I wonder how many types of quantum ...
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Mightn't the cost of a quantum computer be lowered by building it on earth sans cooler and then using it in the frigid vacuum of space?
I'm picturing the control equipment on the inside of an ISS wall with the part that needs being cold being on the outer side.
I imagine this has been considered and if so, was the idea rejected for ...
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Why are superconducting qubits the most popular approach to build a quantum computer?
There are many different physical implementations of qubits: NMR, spin qubit, N color center in diamond, superconducting qubit, trapped ions, photonics quantum computing, topological qubit, etc. ...
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Why do quantum computation models based on open quantum systems receive so little attention?
In almost all research on (universal) quantum computation the common models assumed from the outset are either the quantum circuit model with unitary gates, the measurement-based one-way model or the ...
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Location of "bad" qubits on Sycamore
The Sycamore paper from Google notes that Sycamore is a $54$-qubit quantum processor, but for their experiments only $53$ qubits were working.
The "bad" qubit was on the edge of the array.
Is ...
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What are the physical reasons behind noise/errors in quantum computers?
We know that the current quantum computers are noisy/error-prone. They are susceptible to gate errors (single qubit and multi-qubit), decoherence (relaxation and dephasing), readout error, etc. I want ...
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What design considerations set the frequency bounds for superconducting qubits?
Superconducting qubits generally have frequencies within the range of 4 - 8 GHz. What design considerations give the upper and lower bounds for what is a feasible design. I.e, why can't they be higher ...
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Physical qubit of optical quantum computer
I was researching how optical quantum computers work and discovered a KLM protocol that allows for building quantum gates using linear optics elements like mirrors, beam splitters, and phase shifters. ...
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IBM Q devices' hardware/resource constraints
I tried to look for the resource constraints but so far haven't been able to find them. They are not present in the GitHub repository that usually provides the hardware information for the different ...
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How is a physical qubit measured and how is the result interpreted?
To my understanding, most of the qubits we use today are just Josephson junctions coupled to a resonator that is triggering the qubits to go to different states by using microwave pulses. The same ...
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Current limits on Grover search space
I was wondering why till date Grover search has been implemented only till 3 qubits (corresponding to size of database = 8). Refer this paper
The reason why I ask is that we have much larger sized ...
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Spin precession using a laser
According to Christopher Monroe: "Modular Ion Trap Quantum Networks: Going Big", the hyperfine states of the valence electron in the Yb+ is used as a qubit. I know that we can change the spin ...
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What is the "TRIAD" graph and where can I find more information about it?
I was looking up how to program for a D-Wave machine and I came across this image which says it's the "optimal hardware graph" for a D-Wave machine:
Unfortunately the image seems to have come from ...
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Understanding (theoretical) computing power of quantum computers
I am very new to quantum computing and just try to understand things from a computer scientist's perspective.
In terms of computational power, what I have understood,
100 ideal qubits ... can ...
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When and where was the first use of the term Chimera?
This is along the same lines as the earlier question: When was the first use of the word Entanglement?
I was surprised to discover that when searching for "chimera" in both of Vicky Choi's minor-...
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Can quantum computers be clustered together?
I have been interested in the idea of computer clusting which is about making multiple pysical computer system to act as one whole logical computer system computing the same task at the same time, but ...
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Does the D-Wave 2000Q satisfy DiVincenzo's criteria?
DiVincenzo's criteria for quantum computation are the following:
A scalable physical system with well characterized qubits.
The ability to initialize the state of the qubits to a simple fiducial
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In D-Wave's universal quantum computer, why does the YY term have to be driven along with the linear X term?
D-Wave has a new prototype annealer that uses a Hamiltonian which, if there was enough qubits and sufficient control, would be able to simulate any universal circuit-based quantum computer with at ...
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Can a stored programming model be applied to a Quantum Computer?
A stored programming computer model is that where a central memory is used to store both instructions and data that they operate on. Basically all the classical computers of today that follow the von ...
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Are qubits the only elements required to build a quantum computer?
The power of a quantum computer is often described in terms of how many qubits it has. Does that mean that quantum computers can be run using only qubits, and nothing more? Wouldn't we require some ...
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Randomness from deterministic machine
It is known that in a classical computer we can't generate a purely random number by deterministic process. I am taking a course in Quantum Computing, recently I learnt that using state we can ...
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Transmons and cooper pair box qubits: two islands or a single island and a reservoir
In scientific literature, one typically describes Cooper pair boxes as a small superconducting island coupled to a superconducting reservoir (say, a large ground plane of superconducting metal, or a ...
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