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For a quantum channel with additive Gaussian quantum noise, at the large input energy side, we prove that the one shot capacity is achieved by the thermal noise state for all Gaussian state inputs, it is also true for non-Gaussian input in…

Quantum Physics · Physics 2015-05-13 Xiao-yu Chen

The dissipative dynamics of Gaussian squeezed states (GSS) and coherent superposition states (CSS) are analytically obtained and compared. Time scales for sustaining different quantum properties such as squeezing, negativity of the Wigner…

Quantum Physics · Physics 2009-11-13 L. A. M. Souza , M. C. Nemes , M. França Santos , J. G. Peixoto de Faria

The maximum entropy principle, as applied to quantum systems, is a fundamental prescript positing that for a quantum system for which we only have partial knowledge, the maximum entropy state consistent with the partial knowledge is a…

Quantum Physics · Physics 2025-07-24 Siddhartha Das , Ujjwal Sen

We prove that whenever the coherent information of a one-mode Gaussian channel is non-zero its supremum is achieved for the infinite input power. This is a well established fact for the zero added classical noise, whereas the nonzero case…

Quantum Physics · Physics 2016-02-08 Kamil Bradler

We provide a rigorous treatment of the entanglement properties of two-mode Gaussian states in atmospheric channels by deriving and analyzing the input-output relations for the corresponding entanglement test. A key feature of such turbulent…

Quantum Physics · Physics 2016-07-27 M. Bohmann , A. A. Semenov , J. Sperling , W. Vogel

The capacity of time-varying channels with periodic feedback at the transmitter is evaluated. It is assumed that the channel state information is perfectly known at the receiver and is fed back to the transmitter at the regular…

Information Theory · Computer Science 2007-07-13 Mehdi Ansari Sadrabadi , Mohammad Ali Maddah-Ali , Amir K. Khandani

Joint Gaussian measurements of two quantum systems can be used for quantum communication between remote parties, as in teleportation or entanglement swapping protocols. Many types of physical error sources throughout a protocol can be…

Quantum Physics · Physics 2023-10-03 Alex Kwiatkowski , Ezad Shojaee , Sristy Agrawal , Akira Kyle , Curtis Rau , Scott Glancy , Emanuel Knill

Recently de Palma et al. [IEEE Trans. Inf. Theory 63, 728 (2017)] proved---using Lagrange multiplier techniques---that under a non-zero input entropy constraint, a thermal state input minimizes the output entropy of a pure-loss bosonic…

Quantum Physics · Physics 2017-07-27 Haoyu Qi , Mark M. Wilde , Saikat Guha

It is shown that the capacity of a classical-quantum channel with arbitrary (possibly mixed) states equals to the maximum of the entropy bound with respect to all apriori distributions. This completes the recent result of Hausladen, Jozsa,…

Quantum Physics · Physics 2007-05-23 A. S. Holevo

We prove an upper bound on the private capacity of the single-mode noiseless bosonic wiretap channel. Combined with a previous lower bound, we obtain the low photon-number asymptotic expression for the private capacity. We then show that…

Quantum Physics · Physics 2012-02-07 Ligong Wang , Jeffrey H. Shapiro , Nivedita Chandrasekaran , Gregory W. Wornell

The quantum capacity of a noisy quantum channel determines the maximal rate at which we can code reliably over asymptotically many uses of the channel, and it characterizes the channel's ultimate ability to transmit quantum information…

Quantum Physics · Physics 2021-10-26 Xin Wang

Quantum non-Gaussian states are crucial for the fundamental understanding of non-linear bosonic systems and simultaneously advanced applications in quantum technologies. In many bosonic experiments the important quantum non-Gaussian feature…

Quantum Physics · Physics 2025-10-07 Jan Provazník , Petr Marek , Julien Laurat , Radim Filip

The maximum rates for information transmission through noisy quantum channels has primarily been developed for memoryless channels, where the noise on each transmitted state is treated as independent. Many real world communication channels…

Quantum Physics · Physics 2009-11-10 Garry Bowen , Igor Devetak , Stefano Mancini

As shown by M\'edard, the capacity of fading channels with imperfect channel-state information (CSI) can be lower-bounded by assuming a Gaussian channel input $X$ with power $P$ and by upper-bounding the conditional entropy $h(X|Y,\hat{H})$…

Information Theory · Computer Science 2016-11-15 Adriano Pastore , Tobias Koch , Javier Rodríguez Fonollosa

A general quantum noisy channel is analyzed, wherein the transmitted qubits may experience symmetry-breaking decoherence, along with memory effects. We find the optimal basis not to be fully entangled, but a combination of factorized and…

Quantum Physics · Physics 2015-05-13 Goren Gordon , Gershon Kurizki

We construct a practical method for finding optimal Gaussian probe states for the estimation of parameters encoded by Gaussian unitary channels. This method can be used for finding all optimal probe states, rather than focusing on the…

Quantum Physics · Physics 2016-12-14 Dominik Šafránek , Ivette Fuentes

We give necessary and sufficient conditions for a Gaussian quantum channel to have a dilation involving a passive, i.e., number-preserving unitary. We then establish a normal form of such channels: any passively dilatable channel is the…

Quantum Physics · Physics 2017-04-27 Martin Idel , Robert Koenig

We determine the p->q norms of the Gaussian one-mode quantum-limited attenuator and amplifier and prove that they are achieved by Gaussian states, extending to noncommutative probability the seminal theorem "Gaussian kernels have only…

Mathematical Physics · Physics 2018-08-07 Giacomo De Palma , Dario Trevisan , Vittorio Giovannetti

The achievable rate of information transfer in optical communications is determined by the physical properties of the communication channel, such as the intrinsic channel noise. Bosonic phase-noise channels, a class of non-Gaussian…

Quantum Physics · Physics 2019-08-08 M. T. DiMario , L. Kunz , K Banaszek , F. E. Becerra

Quantum communication theory explores the implications of quantum mechanics to the tasks of information transmission. Many physical channels can be formally described as quantum Gaussian operations acting on bosonic quantum states.…

Quantum Physics · Physics 2015-05-14 Andrea Mari , Vittorio Giovannetti , Alexander S. Holevo
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