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The quasiprobability representation of quantum states addresses two main concerns, the identification of nonclassical features and the decomposition of the density operator. While the former aspect is a main focus of current research, the…

Quantum Physics · Physics 2018-10-26 J. Sperling , I. A. Walmsley

We construct minimum-uncertainty states and a non-negative quasi probability distribution for quantum systems on a finite-dimensional space. We reexamine the theorem of Massar and Spindel for the uncertainty relationof the two unitary…

Quantum Physics · Physics 2019-03-06 T. Hashimoto , A. Hayashi , M. Horibe

We obtain a general formula for the transition probabilities between any state of the algebra of the canonical commutation relations (CCR-algebra) and a squeezed quasifree state. Applications of this formula are made for the case of…

Quantum Physics · Physics 2009-10-31 Horia Scutaru

The convex set of quantum states of a composite $K \times K$ system with positive partial transpose is analysed. A version of the hit and run algorithm is used to generate a sequence of random points covering this set uniformly and an…

Quantum Physics · Physics 2019-02-27 Konrad Szymański , Benoît Collins , Tomasz Szarek , Karol Życzkowski

Quantum graph state is a special class of nonlocal state among multiple quantum particles, underpinning several nonclassical and promising applications such as quantum computing and quantum secret sharing. Recently, establishing quantum…

Quantum Physics · Physics 2025-08-14 Tingxiang Ji , Jianqing Liu , Zheshen Zhang

Quantum transition probabilities and quantum entanglement for two-qubit states of a four level trapped ion quantum system are computed for time-evolving ionic states driven by Jaynes-Cummings Hamiltonians with interactions mapped onto a…

Quantum Physics · Physics 2016-05-25 Victor A. S. V. Bittencourt , Alex E. Bernardini , Massimo Blasone

Hadamard states are generally considered as the physical states for linear quantized fields on curved spacetimes, for several good reasons. Here, we provide a new motivation for the Hadamard condition: for "ultrastatic slab spacetimes" with…

General Relativity and Quantum Cosmology · Physics 2016-08-29 Christopher J Fewster , Rainer Verch

Quantum dots (QDs) are pivotal for the development of quantum technologies, with applications ranging from single-photon sources for secure communication to quantum computing infrastructures. Understanding the electron dynamics within these…

Quantum Physics · Physics 2024-12-20 Markus Sifft , Johannes C. Bayer , Daniel Hägele , Rolf J. Haug

Quasicrystals are tempered distributions $\mu$ which satisfy symmetric conditions on $\mu$ and $\widehat \mu$. This suggests that techniques from time-frequency analysis could possibly be useful tools in the study of such structures. In…

Functional Analysis · Mathematics 2021-06-18 Paolo Boggiatto , Carmen Fernández , Antonio Galbis , Alessandro Oliaro

We show that qubit stabilizer states can be represented by non-negative quasi-probability distributions associated with a Wigner-Weyl-Moyal formalism where Clifford gates are positive state-independent maps. This is accomplished by…

Quantum Physics · Physics 2018-01-03 Lucas Kocia , Peter Love

We study a formal extension of the Dirac equation in the framework of a non-commutative two-sheeted space-time. It is shown that this approach naturally extends the classical Dirac theory by doubling the number of fermionic states, which…

High Energy Physics - Theory · Physics 2009-11-10 Fabrice Petit , Michael Sarrazin

A new geometric representation of qubit and qutrit states based on probability simplexes is used to describe the separability and entanglement properties of density matrices of two qubits. The Peres--Horodecki positive partial transpose…

Quasiperiodic system is an intermediate state between periodic and disordered systems with unique delocalization-localization transition driven by the quasiperiodic potential (QP). One of the intriguing questions is whether the universality…

Disordered Systems and Neural Networks · Physics 2022-10-03 Xunlong Luo , Tomi Ohtsuki

The Clifford group plays a central role in quantum information science. It is the building block for many error-correcting schemes and matches the first three moments of the Haar measure over the unitary group -a property that is essential…

Quantum Physics · Physics 2025-04-17 Lennart Bittel , Jens Eisert , Lorenzo Leone , Antonio A. Mele , Salvatore F. E. Oliviero

We review the definition of hypergeometric coherent states, discussing some representative examples. Then we study mathematical and statistical properties of hypergeometric Schr\"odinger cat states, defined as orthonormalized eigenstates of…

Mathematical Physics · Physics 2019-10-21 Sama Arjika , Manuel Calixto , Julio Guerrero

We construct physical semi-classical states annihilated by the Hamiltonian constraint operator in the framework of loop quantum cosmology as a method of systematically determining the regime and validity of the semi-classical limit of the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Parampreet Singh , Kevin Vandersloot

We explore the relation between noncommutative geometry, in the spectral triple formulation, and quantum mechanics. To this aim, we consider a dynamical theory of a noncommutative geometry defined by a spectral triple, and study its…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Carlo Rovelli

We develop a novel approach to Quantum Mechanics that we call Curved Quantum Mechanics. We introduce an infinite-dimensional K\"ahler manifold ${\cal M}$, that we call the state manifold, such that the cotangent space $T_z^*{\cal M}$ is a…

Quantum Physics · Physics 2024-12-12 Ivan G. Avramidi , Roberto Niardi

A fundamental question asks how uniformly finite sets of pure quantum states can be distributed in a Hilbert space. The Welch bounds address this question, and are saturated by $k$-designs, i.e. sets of states reproducing the $k$-th Haar…

Quantum Physics · Physics 2026-02-27 Riccardo Castellano , Dmitry Grinko , Sadra Boreiri , Nicolas Brunner , Jef Pauwels

Dicke states are permutation-invariant superpositions of qubit computational basis states, which play a prominent role in quantum information science. We consider here two higher-dimensional generalizations of these states: $SU(2)$ spin-$s$…

Quantum Physics · Physics 2026-03-16 Noah B. Kerzner , Federico Galeazzi , Rafael I. Nepomechie
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