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We propose a method to detect genuine quantum correlation for multi-qubit pure states. We then derive a complementarity relations for pure quantum states of N qubits. We prove that in all many-qubit systems there exist strict monogamy laws…

Quantum Physics · Physics 2016-03-21 Xin-wei Zha , Yanpeng Zhang

One way to explore multiparticle entanglement is to ask for maximal entanglement with respect to different bipartitions, leading to the notion of absolutely maximally entangled states or perfect tensors. A different path uses unitary…

Quantum Physics · Physics 2024-01-26 Fabian Bernards , Otfried Gühne

The impossibility of perfect cloning and state estimation are two fundamental results in Quantum Mechanics. It has been conjectured that quantum cloning becomes equivalent to state estimation in the asymptotic regime where the number of…

Quantum Physics · Physics 2010-09-23 Joonwoo Bae , Antonio Acin

We have found a quantum cloning machine that optimally duplicates the entanglement of a pair of $d$-dimensional quantum systems. It maximizes the entanglement of formation contained in the two copies of any maximally-entangled input state,…

Quantum Physics · Physics 2007-05-23 E. Karpov , P. Navez , N. J. Cerf

We establish the best possible approximation to a perfect quantum cloning machine which produces two clones out of a single input. We analyze both universal and state-dependent cloners. The maximal fidelity of cloning is shown to be 5/6 for…

Quantum Physics · Physics 2009-10-30 D. Bruss , D. P. DiVincenzo , A. Ekert , C. A. Fuchs , C. Macchiavello , J. A. Smolin

Due to the Heisemberg uncertainty principle, it is impossible to design a procedure which permits perfect cloning of an arbitrary, unknown "qubit" (the spin or polarization state of a single quantum system)1,2. However, it is believed that…

Quantum Physics · Physics 2007-05-23 Daniele Tommasini

Although perfect copying of unknown quantum systems is forbidden by the laws of quantum mechanics, approximate cloning is possible. A natural way of realizing quantum cloning of photons is by stimulated emission. In this context the…

Quantum Physics · Physics 2009-11-07 Antia Lamas-Linares , Christoph Simon , John C. Howell , Dik Bouwmeester

We show that encrypted cloning of unknown quantum states is possible. Any number of encrypted clones of a qubit can be created through a unitary transformation, and each of the encrypted clones can be decrypted through a unitary…

Quantum Physics · Physics 2026-01-16 Koji Yamaguchi , Achim Kempf

The inherent limitations of physical processes prevent the copying of arbitrary quantum states. Furthermore, even if we only aim to clone two distinct quantum states, it remains impossible unless they are mutually orthogonal. To overcome…

Quantum Physics · Physics 2025-07-24 Zhi-Hao Bi , Jing-Tao Qiu , Xiao-Dong Yu

It is known that the classical information like strings of bits can be copied. In 1982, Wootters and Zurek proposed the quantum no-cloning principle. No-cloning principle says that it is impossible to make an identical copy of an arbitrary…

Quantum Physics · Physics 2026-05-18 Dafa Li

Perfect cloning of a known set of states with arbitrary prior probabilities is possible if we allow the cloner to sometimes fail completely. In the optimal case the probability of failure is at its minimum allowed by the laws of quantum…

Quantum Physics · Physics 2016-09-08 E. Bagan , V. Yerokhin , A. Shehu , E. Feldman , J. A. Bergou

Quantum entanglement and quantum non-locality are known to exhibit monogamy, that is, they obey strong constraints on how they can be distributed among multipartite systems. Quantum correlations that comprise and go beyond entanglement are…

Quantum Physics · Physics 2012-08-03 Alexander Streltsov , Gerardo Adesso , Marco Piani , Dagmar Bruss

We show that, given a general mixed state for a quantum system, there are no physical means for {\it broadcasting\/} that state onto two separate quantum systems, even when the state need only be reproduced marginally on the separate…

Quantum Physics · Physics 2009-10-28 H. Barnum , C. M. Caves , C. A. Fuchs , R. Jozsa , B. Schumacher

A photon in an arbitrary polarization state cannot be cloned perfectly. But suppose that at our disposal we have several copies of an unknown photon. Is it possible to delete the information content of one or more of these photons by a…

Quantum Physics · Physics 2017-05-10 Arun Kumar Pati , Samuel L. Braunstein

Monogamy is a non-classical property that restricts the sharability of quantum correlation among the constituents of a multipartite quantum system. Quantum correlations may satisfy or violate monogamy for quantum states. Here we provide…

Quantum Physics · Physics 2015-02-09 Asutosh Kumar , R. Prabhu , Aditi Sen De , Ujjwal Sen

The impossibility of perfectly copying (or cloning) an arbitrary quantum state is one of the basic rules governing the physics of quantum systems. The processes that perform the optimal approximate cloning have been found in many cases.…

Quantum Physics · Physics 2009-11-11 Valerio Scarani , Sofyan Iblisdir , Nicolas Gisin , Antonio Acin

Two-mode cavities can be prepared in quantum states which represent symmetric multi-qubit states. However, the qubits are impossible to address individually and as such cannot be independently measured or otherwise manipulated. We propose…

Quantum Physics · Physics 2009-11-07 Daniel E. Browne , Martin B. Plenio

Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound…

Quantum Physics · Physics 2009-10-31 Nicolas Gisin

This thesis investigates the entanglement of distinguishable and indistinguishable particles, introducing a new error model for Hardy's test, experimentally verified using superconducting qubits. We address challenges in implementing…

Quantum Physics · Physics 2025-03-12 Soumya Das

we envisage a novel quantum cloning machine, which takes an input state and produces an output state whose success branch can exist in a linear superposition of multiple copies of the input state and the failure branch exist in a…

Quantum Physics · Physics 2009-01-23 Arun Kumar Pati