Quantum computing Definition and 253 Threads

https://www.cs.utexas.edu/news/2018/major-quantum-computing-advance-made-obsolete-ut-grad

In this DOS video, he talks about 5 common misconceptions on QUantum COmputing:

In a 2 level quantum system, should I consider the states |0> and |1|> to be qubits by themselves? Or is only the SUPERPOSITION of these two states, \alpha |0> + \beta |1> considered to be a qubit?

I'm watching a lecture on the intro to quantum computing. See the attached image which will be useful as I describe my question. So the professor says that we have this single photon and it's in this state, ## | 0 > ##. He states that when we send this photon through a beam splitter that it...

I am doing a project on stabilizer code, and I keep running into a term about qubits and leakage. What does leakage mean?

Hello, I am close to finishing my undergraduate degree in Computer Engineering, and I am very interested in pursuing graduate studies. For a long time, I have been passionate about computer science and I've been looking into the research done in various labs in the schools that I'm considering...

Does quantum computing have any profound implications for the memory capacity of computers? It's often possible to replace a large table of data by a smaller set of numbers and an algorithm that reconstructs each entry of the table using the smaller data set. Will quantum computers made such...

Hi! So I'm studying Gover's Algorithm and I have this doubt: Does 'Phase inversion gate' grows exponentially? I mean, if I want to signal the one combination that is the answer, I must be able to represent all 2^N states, where N is the number of qubits in the system. How do I do this without...

I am a middle-school student and I have just recently finished a course in Honors Physics and have already started one on AP Calculus. I have been reading quite a few books on quantum physics. I just recently started one on quantum computing and it is very interesting. Interesting enough I might...

Due to required reversibility, classical function (f(a)=y^a \mod N) in Shor's algorithm needs a lot of auxiliary qubits. I was afraid that their later treatment might influence the computation - and just got confirmation from Peter Shor himself: that we need to "uncompute" these auxiliary...

"Just when it was looking like the underdog, classical computing is striking back. IBM has come up with a way to simulate quantum computers that have 56 quantum bits, or qubits, on a non-quantum supercomputer – a task previously thought to be impossible. The feat moves the goalposts in the fight...

Hey all, I'm a student in university who wants to Double Major in Computer Engineering and Physics or Computer Engineering and Mathematics. Ideally I want to get some time in working on quantum computers and some time in working on advanced AI, so one of the big things I want to do is pick the...

Hey all, I'm a student in university who wants to Double Major in Computer Engineering and Physics or Mathematics. Ideally I want to get some time in working on quantum computers and some time in working on advanced AI, so one of the big things I want to do is pick the community's brain on...

Let's say an entire city runs on a network run by quantum computing. Fail safe locks are run by this network. Would triggering a massive unlocking of the city be a simple matter of killing the main power to shut down the quantum network (by shutting down the cooling systems)? It seems logical...

Hello, I’m currently an Undergraduate Computer Engineer at UIC and minoring in physics. I have become more and more interested in Quantum Computing and its related fields. I plan on continuing my masters in Electrical engineering (Nano - technology). I was wondering if you could help me out in...

I am well aware that QC-related graduate programs are competitive so I am preparing myself for a rejection. Not because I'm unconfident. But because everyone should have a backup plan just in case. I haven't applied yet because I'm about to take the GRE. I really do enjoy both quantum physics...

Two photons arrive at a hypothetical 50:50 Beam-Splitter with no phase shift between reflected and transmitted modes. One enters the Left side and the other the Bottom side of the BS as shown in Fig.1 of the link below: https://drive.google.com/open?id=0B5JsDLKoUSA5emk5Qk9nUHVIelE Each photon...

Hello everyone! So I was looking at Shor Algorithm for prime factorization and I have some doubts in the arithmetic part. Let's define a function f that : f(x) = ax mod N. The middle step in shor algorithm is to calculate, simultaneously, all values of f. In some papers and books, I saw some...

Hello. What is the best quantum simulator till now? We could select two categories: a) Best full simulator able to solve the equations describing a system in 3D and watching its temporal evolution. b) Best digital simulator, algorithm analyzer. For the second options I have some candidates...

Hello. What is a good book to learn Quantum Computing? I've being looking for the most common ones and reading some reviews at Amazon, and created this list: A Short Introduction to Quantum Information and Quantum Computation, Le Bellac, 2006 An Introduction to Quantum Computing Algorithms...

I am a computer science under graduate,I am more interested in scientific research, so I am preparing to enrol myself masters in quantum computing or simulation sciences. before i join i want to research what are the scope and job opportunities are available for simulation sciences(like...

Is there any opportunities to start Quantum Computing career after BSc Physics?

I'm in a proyect to simulate quantum circuits in robots like in this paper ( http://ieeexplore.ieee.org/document/4215941/ ) ,the first thing that i need to do is to simulated the circuit that is in that paper: But I'm having trouble understanding how the hadamard gate affects the "C"...

Hello, I’m currently an Undergraduate Computer Engineer at UIC and minoring in physics. I have become more and more interested in Quantum Computing and its related fields. I plan on continuing my masters in Electrical engineering and taking graduate level physics classes at the same time. I...

Hello I am studying Software Engineer but I am interested in Quantum Computing, I never had any serious relationships with physics so i need to start from somewhere, Can you help me?

I am planning to take go into quantum computing. I am a Computer Engineer with a minor in physics with a focus on modern quantum theory. I was wondering if I take undergraduate and graduate level quantum physics classes would be enough for me to have a solid background on the subject before I do...

With the development of quantum computing, just how much could it improve our lives. Obviously faster computing, but could we begin to do things than conventional computer can't?

I have been reading lately about the University of Sussex work on large scale quantum computing that doesn't require the Laser beam approach to controlling the atom. This seems like a huge breakthrough in the development of quantum computers however a forum search doesn't have any mention of it...

(tl;dr: Interested in the hardware side of quantum computing, but don't want to commit to staying in academia. Is getting an industry job in quantum computing going to be realistic in 6-8 years? Are there other viable engineering-type jobs available if I end up getting a PhD in this field?) Hi...

I am a physics student from Spain and hopefully I will be finishing my degree in physics (4y) by next June. I am trying to decide on a Master's program to study but I am finding very difficult to decide since there are so many oportunities and so diverse specially when looking for programs...

Hi. I was wondering if you could help me out a bit here. I have a choice to take either a module on stochastic dynamics in statistical mechanics or quantum computing for my masters. Both seem really interesting so it’s a close tie between which one has more current/future applications. The...

I've been doing a course on Quantum Computing and I haven't managed to figure out so far how entanglement would be a useful resource on a general purpose quantum computer. By general purpose quantum computer I mean some theoretical device that could possibly replace current classical computers...

Hi all, I am sure some of you have heard of Simon's algorithm that calculates a secret string s when given a black box. Basically, let's say we have a qubit x that is n digits long. Now the black box contains a function f that outputs f(x+s) where s is the mystery string and + is bit-wise modulo...

As a senior in college studying IT , I am just learning the barebones principles about database construction, Object oreinted programming, with the intent of preperation for entering the job market. But I have always had a passion for Computers and technology in general. I understand that...

Quantum computers are in use now.

Can any expert help me in explaining how this example below get the reduced density matrix from the density matrix in bipartite system. $$\rho =\frac{1}{4}\begin{pmatrix} 1 & 1 & cos(\frac{\alpha}{2})-sin(\frac{\alpha}{2}) & cos(\frac{\alpha}{2})+sin(\frac{\alpha}{2}) \\ 1 & 1 &...

Hi, I am an undergraduate student from India. Pursuing double major in Physics and Mechanical Engineering. I have completed 4 semesters(2 years) of my college. I had taken a class titled "Quantum information and computing" and it interested me a lot. I really love math and computations...

So in quantum mechanics, there are at least three different kinds of measurement operators: the General, the Projective, and the Positive Operator-Valued (POVM). They have different properties and relationships. In a typical QM book, these are not delineated, but in Quantum Computing they are...

This week, in Sydney, there was the announcement of not one but TWO Quantum Computing centres opening at two rival universities (UNSW and USYD). There was a feature on one of the current affairs shows here with the very charismatic guitar-playing professor of one of the centres, which has had a...

In my opinion, Justin Trudeau is the epitome of what a Prime Minister should be. Here, in this video, Justin talks about quantum computing:

To what degree should I study each of these fields in order to be prepared for a career in quantum computing R&D? Electrical Engineering Computer Science Physics I plan to major in all three topics, but with which program(s) should I pursue higher education? I realize computer engineering is...

Hey Everyone! I'm new here as a member but not as a visitor. I've looked upon these forums for answers, guidance, and general informative information. I liked what I saw so much that I decided to join. A little about me: My name is Edward, I live in Tennessee and am currently working my way...

Hello I have recently taken interest in physics and mostly Quantum computing and i was wondering what is the best way of tackling that field . Is it to have a major in Computer Science and possibly a major/minor in physics? or to aim for colleges that have specific classes of quantum...

This is Exercise 2.20 in Nielsen and Chuang's Quantum Computation and Quantum Information, on page 71. Suppose $A'$ and $A''$ are matrix representations of an operator $A$ on a vector space $V$ with respect to two different orthonormal bases, $|v_i\rangle$ and $|w_i\rangle$. Then the elements...

Exercise 2.24 on page 71 of Nielsen and Chuang's Quantum Computation and Quantum Information asks the reader to show that a positive operator is necessarily Hermitian. There is a hint given; namely, that you first show an arbitrary operator can be written $A=B+iC$, where $B$ and $C$ are...

Hello, Am an undergraduate student of physics(hons) and want to work on Quantum Computing in future. Can anybody please suggest how I should go about it? Thanks in advance

Hello everyone, I'm an undergraduate double majoring in physics and math. I have one year left after this one, then I plan to go to grad school for theoretical physics (not sure what field yet). My professor keeps suggesting the physics side of quantum computing as a good career route and I'm...

I am beginning a study I have long wanted to engage in: quantum computing. This is a field lying at the intersection of mathematics, physics, computer science, and electrical engineering - all topics I studied, to varying levels. From time to time, I plan on posting notes and summaries that...

Hello All, I've just recently read David Deutsch and Michael Lockwood article about Time Travel of 1994 in Scientific American.They stated,that although among the physicists Everett's theory remains controversial,it has no alternatives in Quantum Cosmology and Quantum Computing.Is it really...

I have seen other posts here on PF and I have done some internet research. In what I have found so far it is hard to get a plain English answer around the number system that is used in quantum computing. A lot of references are made to binary with a superposition. Is there a way to simple way...