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Quantum computing relies on processing information within a quantum system with many continuous degrees of freedom. The practical implementation of this idea requires complete control over all of the 2^n independent amplitudes of a…

Condensed Matter · Physics 2007-05-23 M. I. Dyakonov

While quantum circuits built from two-particle dual-unitary (maximally entangled) operators serve as minimal models of typically nonintegrable many-body systems, the construction and characterization of dual-unitary operators themselves are…

Quantum Physics · Physics 2023-01-20 Suhail Ahmad Rather , S. Aravinda , Arul Lakshminarayan

We describe in detail a general strategy for implementing a conditional geometric phase between two spins. Combined with single-spin operations, this simple operation is a universal gate for quantum computation, in that any unitary…

Quantum Physics · Physics 2015-06-26 A. Ekert , M. Ericsson , P. Hayden , H. Inamori , J. A. Jones , D. K. L. Oi , V. Vedral

We propose a general scheme for dissipatively preparing arbitrary pure quantum states on a multipartite qubit register in a finite number of basic control blocks. Our "splitting-subspace" approach relies on control resources that are…

Quantum Physics · Physics 2013-11-19 Giacomo Baggio , Francesco Ticozzi , Lorenza Viola

To observe or control a quantum system, one must interact with it via an interface. This letter exhibits simple universal quantum interfaces--quantum input/output ports consisting of a single two-state system or quantum bit that interacts…

Quantum Physics · Physics 2007-05-23 Seth Lloyd , Andrew J. Landahl , Jean-Jacques E. Slotine

Quantum computers are special purpose machines that are expected to be particularly useful in simulating strongly correlated chemical systems. The quantum computer excels at treating a moderate number of orbitals within an active space in a…

A software product line models the variability of highly configurable systems. Complete exploration of all valid configurations (the configuration space) is infeasible as it grows exponentially with the number of features in the worst case.…

Quantum Physics · Physics 2023-07-28 Joshua Ammermann , Tim Bittner , Domenik Eichhorn , Ina Schaefer , Christoph Seidl

To go beyond quantum optics in free-space setups, atom-light interfaces with structured photonic environments are often employed to realize unconventional quantum electrodynamics (QED) phenomena. However, when employed as quantum buses,…

Quantum Physics · Physics 2025-03-03 Xin Wang , Huai-Bing Zhu , Tao Liu , Franco Nori

Quantum computation offers the potential to solve fundamental yet otherwise intractable problems across a range of active fields of research. Recently, universal quantum-logic gate sets - the building blocks for a quantum computer - have…

Completely positive quantum operations are frequently discussed in the contexts of statistical mechanics and quantum information. They are customarily given by maps forming positive operator-values measures. To intuitively understand…

Statistical Mechanics · Physics 2015-01-23 Sumiyoshi Abe , Yasuyuki Matsuo

We give necessary conditions for the mixing problem in bipartite case, which are independent of eigenvalues and based on algebraic-geometric invariants of the bipartite states. One implication of our results is that for some special…

Quantum Physics · Physics 2007-05-23 Hao Chen

Quantum conditions on the control of dynamics of a system coupled to an environment are obtained. Specifically, consider a system initially in a system subspace $H_{0}$ of dimensionality $M_{0}$, which evolves to populate system subspaces…

Quantum Physics · Physics 2009-11-13 Lian-Ao Wu , Arjun Bharioke , Paul Brumer

While quantum computers are capable of simulating many quantum systems efficiently, the simulation algorithms must begin with the preparation of an appropriate initial state. We present a method for generating physically relevant quantum…

Quantum Physics · Physics 2009-05-29 Nicholas J. Ward , Ivan Kassal , Alán Aspuru-Guzik

One of the main aims in the field of quantum simulation is to achieve a quantum speedup, often referred to as "quantum computational supremacy", referring to the experimental realization of a quantum device that computationally outperforms…

Quantum Physics · Physics 2018-04-18 J. Bermejo-Vega , D. Hangleiter , M. Schwarz , R. Raussendorf , J. Eisert

In Ref. [Phys. Rev. A 100, 062317 (2019)], the authors reported an algorithm to implement, in a circuit-based quantum computer, a general quantum measurement (GQM) of a two-level quantum system, a qubit. Even though their algorithm seems…

Quantum Physics · Physics 2023-02-10 Douglas F. Pinto , Marcelo S. Zanetti , Marcos L. W. Basso , Jonas Maziero

Quantum algorithms are a very promising field. However, creating and manipulating these kind of algorithms is a very complex task, specially for software engineers used to work at higher abstraction levels. The work presented here is part…

It is first pointed out that there is a common mathematical model for the universe and the quantum computer. The former is called the histories approach to quantum mechanics and the latter is called measurement based quantum computation.…

Quantum Physics · Physics 2022-09-01 Stan Gudder

We introduce a class of bipartite operators acting on $\mathcal{H} \otimes \mathcal{H}$ ($\mathcal{H}$ being an $n$-dimensional Hilbert space) defined by a set of $n$ Completely Different Permutations CDP. Bipartite operators are of…

Mathematical Physics · Physics 2017-12-12 Marek Mozrzymas , Dariusz Chruściński , Gniewomir Sarbicki

Randomization of quantum states is the quantum analogue of the classical one-time pad. We present an improved, efficient construction of an approximately randomizing map that uses O(d/epsilon^2) Pauli operators to map any d-dimensional…

Quantum Physics · Physics 2018-03-22 Paul A. Dickinson , Ashwin Nayak

As we begin to reach the limits of classical computing, quantum computing has emerged as a technology that has captured the imagination of the scientific world. While for many years, the ability to execute quantum algorithms was only a…

Quantum Physics · Physics 2020-11-12 Bela Bauer , Sergey Bravyi , Mario Motta , Garnet Kin-Lic Chan