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Related papers: Universality of Computation in Real Quantum Theory

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The universality theorem in quantum computing states that any quantum computational task can be decomposed into a finite set of logic gates operating on one and two qubits. However, the process of such decomposition is generally…

Quantum Physics · Physics 2023-01-19 Chao Fang , Ye Wang , Ke Sun , Jungsang Kim

What resources are universal for quantum computation? In the standard model, a quantum computer consists of a sequence of unitary gates acting coherently on the qubits making up the computer. This paper shows that a very different model…

Quantum Physics · Physics 2009-11-07 Michael A. Nielsen

According to the statistical interpretation of quantum theory, quantum computers form a distinguished class of probabilistic machines (PMs) by encoding n qubits in 2n pbits (random binary variables). This raises the possibility of a…

Quantum Physics · Physics 2007-05-23 P. Gralewicz

A local conception is proposed to reconcile quantum theory with general relativity, which allows one to avoid some difficulties --- as e.g. vacuum catastrophe --- of the global approach.

General Relativity and Quantum Cosmology · Physics 2007-05-23 Peter Hrasko

Universal gate sets for quantum computation, when single and two qubit operations are accessible, include both Hermitian and non-Hermitian gates. Here we utilize the fact that any single-qubit operator may be implemented as two Hermitian…

Quantum Physics · Physics 2025-12-03 Ben Zindorf , Sougato Bose

The conventional paradigm of quantum computing is discrete: it utilizes discrete sets of gates to realize bitstring-to-bitstring mappings, some of them arguably intractable for classical computers. In parameterized quantum approaches, the…

Quantum Physics · Physics 2025-12-12 Adrián Pérez-Salinas , Mahtab Yaghubi Rad , Alice Barthe , Vedran Dunjko

Quantum nonlocality without entanglement (Q-NWE) encapsulates nonlocal behavior of multipartite product states as they may entail global operation for optimal decoding of the classical information encoded within. Here we show that the…

Quantum Physics · Physics 2020-03-25 Some Sankar Bhattacharya , Sutapa Saha , Tamal Guha , Manik Banik

We propose to use a buckled plate as a qubit, where a double-well potential is mechanically produced by pushing the plate from both the sides. The right and left positions of the plate are assigned to be quantum states $|0\rangle $ and…

Quantum Physics · Physics 2023-06-27 Motohiko Ezawa , Shun Yasunaga , Akio Higo , Tetuya Iizuka , Yoshio Mita

We present a theoretical analysis of the paradigm of encoded universality, using a Lie algebraic analysis to derive specific conditions under which physical interactions can provide universality. We discuss the significance of the tensor…

Quantum Physics · Physics 2007-05-23 J. Kempe , D. Bacon , D. P. DiVincenzo , K. B. Whaley

The mathematical notion of incompleteness (eg of rational numbers, Turing-computable functions, and arithmetic proof) does not play a key role in conventional physics. Here, a reformulation of the kinematics of quantum theory is attempted,…

Quantum Physics · Physics 2007-05-23 T. N. Palmer

The paradigm of measurement-based quantum computation opens new experimental avenues to realize a quantum computer and deepens our understanding of quantum physics. Measurement-based quantum computation starts from a highly entangled…

We introduce group surface codes, which are a natural generalization of the $\mathbb{Z}_2$ surface code, and equivalent to quantum double models of finite groups with specific boundary conditions. We show that group surface codes can be…

Quantum Physics · Physics 2026-03-06 Naren Manjunath , Vieri Mattei , Apoorv Tiwari , Tyler D. Ellison

An investigation of an optimal universal unitary Controlled-NOT gate that performs a specific operation on two unknown states of qubits taken from a great circle of the Bloch sphere is presented. The deep analogy between the optimal…

Quantum Physics · Physics 2010-11-02 Michael Siomau , Stephan Fritzsche

Quantum computation is based on implementing selected unitary transformations which represent algorithms. A generalized optimal control theory is used to find the driving field that generates a prespecified unitary transformation. The…

Quantum Physics · Physics 2009-11-07 Jose P. Palao , Ronnie Kosloff

We show that quantum theory allows for transformations of black boxes that cannot be realized by inserting the input black boxes within a circuit in a pre-defined causal order. The simplest example of such a transformation is the classical…

Quantum Physics · Physics 2013-10-29 G. Chiribella , G. M. D'Ariano , P. Perinotti , B. Valiron

Quantum computations usually take place under the control of the classical world. We introduce a Classically-controlled Quantum Turing Machine (CQTM) which is a Turing Machine (TM) with a quantum tape for acting on quantum data, and a…

Quantum Physics · Physics 2016-10-11 Simon Perdrix , Philippe Jorrand

We analyze the problem of a quantum computer in a correlated environment protected from decoherence by QEC using a perturbative renormalization group approach. The scaling equation obtained reflects the competition between the dimension of…

Quantum Physics · Physics 2007-05-23 E. Novais , Eduardo R. Mucciolo , Harold U. Baranger

The information obtained from the operation of a quantum gate on only two complementary sets of input states is sufficient to estimate the quantum process fidelity of the gate. In the case of entangling gates, these conditions can be used…

Quantum Physics · Physics 2017-08-23 Holger F. Hofmann , Ryo Okamoto , Shigeki Takeuchi

Simulating physical systems on near-term quantum computers often requires preparing states within constrained subspaces, like those with fixed particle number or spin. We use Lie algebraic techniques to prove that hardware-efficient gates…

Quantum Physics · Physics 2026-05-05 Andreas Stergiou , Nicolas PD Sawaya

Quantum walk has been regarded as a primitive to universal quantum computation. By using the operations required to describe the single particle discrete-time quantum walk on a position space we demonstrate the realization of the universal…

Quantum Physics · Physics 2021-06-16 Shivani Singh , Prateek Chawla , Anupam Sarkar , C. M. Chandrashekar