Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1506.09031 · Physical Review A

Generalized interaction-free evolutions

Benedetto Militello, Dariusz Chruściński, ANTONINO MESSINA, Paweł Należyty, Anna Napoli

Published Feb 16, 2016• 6 citations
arXivHTMLPDF

Abstract

A thorough analysis of the evolutions of bipartite systems characterized by the ``effective absence'' of interaction between the two subsystems is reported. First, the connection between the concepts underlying interaction-free evolutions (IFE) and decoherence-free subspaces (DFS) is explored, showing intricate relations between these concepts. Second, starting from this analysis and inspired by a generalization of DFS already known in the literature, we introduce the notion of generalized IFE (GIFE), also providing a useful characterization that allows one to develop a general scheme for finding GIFE states.

DOI
10.1103/physreva.93.022113

Related papers

Theory of initialization-free decoherence-free subspaces and subsystems

Alireza Shabani, Daniel A. Lidar

We introduce a generalized theory of decoherence-free subspaces and subsystems (DFSs), which do not require accurate initialization. We derive a set of conditions for the existence of DFSs within this generalized framework. By relaxing the initialization requirement we show that a DFS can tolerate arbitrarily large preparation errors. This has potentially significant implications for experiments involving DFSs, in particular for the experimental implementation, over DFSs, of the large class of quantum algorithms which can function with arbitrary input states.

arXiv:quant-ph/0505051•Physical Review A•Oct 3, 2005•101 citations

S-matrix approach to the construction of decoherence-free subspaces

Moshe Shapiro, Paul W. Brumer

Analyzing the S matrices associated with a host of relaxation processes allows one, using extra ``chaperon'' states, to construct a decoherence-free subspace (DFS) that is immune to the effects of relaxation. The method does not require knowledge of the system-bath Hamiltonian, which is rarely known. Thus, a DFS can be constructed directly from experimentally determined relaxation and dephasing rates of the relevant decoherence processes. Although the method requires resetting the coefficients of the chaperon states at various times, this resetting does not require determining the coefficients of the states belonging to the DFS that one uses for control, computations, or information storage.

Physical Review A•Nov 18, 2002•9 citations

Interaction-free evolving states of a bipartite system

Anna Napoli, M. Guccione, Antonio Messina +1 more

We show that two interacting physical systems may admit entangled pure or nonseparable mixed states evolving in time as if the mutual interaction Hamiltonian were absent. In this paper we define these interaction-free evolving (IFE) states and characterize their existence for a generic binary system described by a time-independent Hamiltonian. A comparison between IFE subspace and the decoherence-free subspace is reported. The set of all pure IFE states is explicitly constructed for a nonhomogeneous spin-star-system model

arXiv:1402.6448•Physical Review A•Jun 5, 2014•9 citations

Interaction-free evolution in the presence of time-dependent Hamiltonians

Dariusz Chruściński, ANTONINO MESSINA, Benedetto Militello +1 more

The generalization of the concept of interaction-free evolutions (IFE) [Napoli et al., Phys. Rev. A 89, 062104 (2014)] to the case of time-dependent Hamiltonians is discussed. It turns out that the time-dependent case allows for much richer structures of interaction-free states and interaction-free subspaces. The general condition for the occurrence of IFE is found and exploited to analyze specific situations. Several examples are presented, each one associated to a class of Hamiltonians with specific features.

arXiv:1502.06391•Physical Review A•Apr 20, 2015•10 citations

Quantum Open System Theory: Bipartite Aspects

T. Yu, Joseph H. Eberly

We demonstrate in straightforward calculations that even under ideally weak noise the relaxation of bipartite open quantum systems contains elements not previously encountered in quantum noise physics. While additivity of decay rates is known to be generic for decoherence of a single system, we demonstrate that it breaks down for bipartite coherence of even the simplest composite systems.

arXiv:quant-ph/0603256•Physical Review Letters•Oct 3, 2006•632 citations

Theory of decoherence-free fault-tolerant universal quantum computation

Julia Kempe, Dave Bacon, Daniel A. Lidar +1 more

Universal quantum computation on decoherence-free subspaces and subsystems (DFSs) is examined with particular emphasis on using only physically relevant interactions. A necessary and sufficient condition for the existence of decoherence-free (noiseless) subsystems in the Markovian regime is derived here for the first time. A stabilizer formalism for DFSs is then developed which allows for the explicit understanding of these in their dual role as quantum error correcting codes. Conditions for the existence of Hamiltonians whose induced evolution always preserves a DFS are derived within this stabilizer formalism. Two possible collective decoherence mechanisms arising from permutation symmetries of the system-bath coupling are examined within this framework. It is shown that in both cases universal quantum computation which always preserves the DFS (natural fault-tolerant computation) can be performed using only two-body interactions. This is in marked contrast to standard error correcting codes, where all known constructions using one- or two-body interactions must leave the code space during the on-time of the fault-tolerant gates. A further consequence of our universality construction is that a single exchange Hamiltonian can be used to perform universal quantum computation on an encoded space whose asymptotic coding efficiency is unity. The exchange Hamiltonian, which is naturally present in many quantum systems, is thus asymptotically universal.

arXiv:quant-ph/0004064•Physical Review A•Mar 20, 2001•534 citations
A thorough analysis of the evolutions of bipartite systems characterized by the ``effective absence'' of interaction between the two subsystems is reported. First, the connection between the concepts underlying interaction-free evolutions (IFE) and decoherence-free subspaces (DFS) is explored, showing intricate relations between these concepts. Second, starting from this analysis and inspired by a generalization of DFS already known in the literature, we introduce the notion of generalized IFE (GIFE), also providing a useful characterization that allows one to develop a general scheme for finding GIFE states.
We introduce a generalized theory of decoherence-free subspaces and subsystems (DFSs), which do not require accurate initialization. We derive a set of conditions for the existence of DFSs within this generalized framework. By relaxing the initialization requirement we show that a DFS can tolerate arbitrarily large preparation errors. This has potentially significant implications for experiments involving DFSs, in particular for the experimental implementation, over DFSs, of the large class of quantum algorithms which can function with arbitrary input states.
Analyzing the S matrices associated with a host of relaxation processes allows one, using extra ``chaperon'' states, to construct a decoherence-free subspace (DFS) that is immune to the effects of relaxation. The method does not require knowledge of the system-bath Hamiltonian, which is rarely known. Thus, a DFS can be constructed directly from experimentally determined relaxation and dephasing rates of the relevant decoherence processes. Although the method requires resetting the coefficients of the chaperon states at various times, this resetting does not require determining the coefficients of the states belonging to the DFS that one uses for control, computations, or information storage.
We show that two interacting physical systems may admit entangled pure or nonseparable mixed states evolving in time as if the mutual interaction Hamiltonian were absent. In this paper we define these interaction-free evolving (IFE) states and characterize their existence for a generic binary system described by a time-independent Hamiltonian. A comparison between IFE subspace and the decoherence-free subspace is reported. The set of all pure IFE states is explicitly constructed for a nonhomogeneous spin-star-system model
The generalization of the concept of interaction-free evolutions (IFE) [Napoli et al., Phys. Rev. A 89, 062104 (2014)] to the case of time-dependent Hamiltonians is discussed. It turns out that the time-dependent case allows for much richer structures of interaction-free states and interaction-free subspaces. The general condition for the occurrence of IFE is found and exploited to analyze specific situations. Several examples are presented, each one associated to a class of Hamiltonians with specific features.
Universal quantum computation on decoherence-free subspaces and subsystems (DFSs) is examined with particular emphasis on using only physically relevant interactions. A necessary and sufficient condition for the existence of decoherence-free (noiseless) subsystems in the Markovian regime is derived here for the first time. A stabilizer formalism for DFSs is then developed which allows for the explicit understanding of these in their dual role as quantum error correcting codes. Conditions for the existence of Hamiltonians whose induced evolution always preserves a DFS are derived within this stabilizer formalism. Two possible collective decoherence mechanisms arising from permutation symmetries of the system-bath coupling are examined within this framework. It is shown that in both cases universal quantum computation which always preserves the DFS (natural fault-tolerant computation) can be performed using only two-body interactions. This is in marked contrast to standard error correcting codes, where all known constructions using one- or two-body interactions must leave the code space during the on-time of the fault-tolerant gates. A further consequence of our universality construction is that a single exchange Hamiltonian can be used to perform universal quantum computation on an encoded space whose asymptotic coding efficiency is unity. The exchange Hamiltonian, which is naturally present in many quantum systems, is thus asymptotically universal.