Combining dynamical decoupling with fault-tolerant quantum computation (2009)
Ng, Hui Khoon, Lidar, Daniel A., Preskill, John
We study how dynamical decoupling (DD) pulse sequences can improve the reliability of quantum computers. We prove upper bounds on the accuracy of DD-protected quantum gates and derive sufficient...
High fidelity quantum gates via dynamical decoupling (2009)
West, Jacob R., Lidar, Daniel A., Fong, Bryan H., Gyure, Mark F., Peng, Xinhua, Suter, Dieter
Realizing the theoretical promise of quantum computers will require overcoming decoherence -- the loss of "quantumness" due to the inevitable interaction between the quantum computer and its...
Near-optimal dynamical decoupling of a qubit (2009)
West, Jacob R., Fong, Bryan H., Lidar, Daniel A.
We present a near-optimal quantum dynamical decoupling scheme that eliminates general decoherence of a qubit to order n using O(n^2) pulses, an exponential decrease in pulses over all previous...
Arbitrarily Accurate Dynamical Control in Open Quantum Systems (2009)
Khodjasteh, Kaveh, Lidar, Daniel A., Viola, Lorenza
We show that open-loop dynamical control techniques may be used to synthesize unitary transformations in open quantum systems in such a way that decoherence is perturbatively compensated for to a...
Scheme for fault-tolerant holonomic computation on stabilizer codes (2009)
Oreshkov, Ognyan, Brun, Todd A., Lidar, Daniel A.
This paper generalizes and expands upon the work [Phys. Rev. Lett. 102, 070502 (2009)] where we introduced a scheme for fault-tolerant holonomic quantum computation (HQC) on stabilizer codes. HQC is...
Entanglement and area law with a fractal boundary (2009)
Hamma, Alioscia, Lidar, Daniel A., Severini, Simone
Quantum systems with short range interactions are known to respect an area law for the entanglement entropy: the von Neumann entropy S associated to a bipartition scales with the boundary p between...
Channel-Optimized Quantum Error Correction (2008)
Taghavi, Soraya, Kosut, Robert L., Lidar, Daniel A.
We develop a theory for finding quantum error correction (QEC) procedures which are optimized for given noise channels. Our theory accounts for uncertainties in the noise channel, against which our...
Bang-bang control of a qubit coupled to a quantum critical spin bath (2008)
Rossini, Davide, Facchi, Paolo, Fazio, Rosario, Florio, Giuseppe, Lidar, Daniel A., Pascazio, Saverio, ...
We analytically and numerically study the effects of pulsed control on the decoherence of a qubit coupled to a quantum spin bath. When the environment is critical, decoherence is faster and we show...
Operator quantum error correction for continuous dynamics (2008)
Oreshkov, Ognyan, Lidar, Daniel A., Brun, Todd A.
We study the conditions under which a subsystem code is correctable in the presence of noise that results from continuous dynamics. We consider the case of Markovian dynamics as well as the general...
Fault-tolerant holonomic quantum computation (2008)
Oreshkov, Ognyan, Brun, Todd A., Lidar, Daniel A.
We explain how to combine holonomic quantum computation (HQC) with fault tolerant quantum error correction. This establishes the scalability of HQC, putting it on equal footing with other models of...
Optimal Dynamical Decoherence Control of a Qubit (2008)
Gordon, Goren, Kurizki, Gershon, Lidar, Daniel A.
A theory of dynamical control by modulation for optimal decoherence reduction is developed. It is based on the non-Markovian Euler-Lagrange equation for the energy-constrained field that minimizes...
Adiabatic approximation for many body systems and quantum computation (2008)
Hamma, Alioscia, Lidar, Daniel A.
This paper has been withdrawn as it has been superseded by 0808.2697
Encoding One Logical Qubit Into Six Physical Qubits (2008)
Shaw, Bilal, Wilde, Mark M., Oreshkov, Ognyan, Kremsky, Isaac, Lidar, Daniel A.
We discuss two methods to encode one qubit into six physical qubits. Each of our two examples corrects an arbitrary single-qubit error. Our first example is a degenerate six-qubit quantum...
Bang-Bang control of a qubit coupled to a quantum critical spin bath (2008)
Rossini, Davide, Facchi, Paolo, Fazio, Rosario, Florio, Giuseppe, Lidar, Daniel A., Pascazio, Saverio, ...
We analytically and numerically study the effects of pulsed control on the decoherence of a qubit coupled to a quantum spin bath. When the environment is critical, decoherence is faster and we show...
Grace, Matthew D., Brif, Constantin, Rabitz, Herschel, Lidar, Daniel A., Walmsley, Ian A., Kosut, Robert L.
This work studies the feasibility of optimal control of high-fidelity quantum gates in a model of interacting two-level particles. One particle (the qubit) serves as the quantum information...
The Spin Density Matrix II: Application to a system of two quantum dots (2007)
Kunikeev, Sharif D., Lidar, Daniel A.
This work is a sequel to our work "The Spin Density Matrix I: General Theory and Exact Master Equations" (eprint arXiv:0708.0644 [cond-mat]). Here we compare pure- and pseudo-spin dynamics using as...
The Spin Density Matrix I: General Theory and Exact Master Equations (2007)
Kunikeev, Sharif D., Lidar, Daniel A.
We consider a scenario where interacting electrons confined in quantum dots (QDs) are either too close to be resolved, or we do not wish to apply measurements that resolve them. Then the physical...
Non-Markovian dynamics of a qubit coupled to an Ising spin bath (2007)
Krovi, Hari, Oreshkov, Ognyan, Ryazanov, Mikhail, Lidar, Daniel A.
We study the analytically solvable Ising model of a single qubit system coupled to a spin bath. The purpose of this study is to analyze and elucidate the performance of Markovian and non-Markovian...
Towards Fault Tolerant Adiabatic Quantum Computation (2007)
I show how to protect adiabatic quantum computation (AQC) against decoherence and certain control errors, using a hybrid methodology involving dynamical decoupling, subsystem and stabilizer codes,...
Geraci, Joseph, Lidar, Daniel A.
We present an efficient quantum algorithm for the exact evaluation of either the fully ferromagnetic or anti-ferromagnetic q-state Potts partition function Z for a family of graphs related to...
Grace, Matthew, Brif, Constantin, Rabitz, Herschel, Walmsley, Ian A., Kosut, Robert L., Lidar, Daniel A.
Methods of optimal control are applied to a model system of interacting two-level particles (e.g., spin-half atomic nuclei or electrons or two-level atoms) to produce high-fidelity quantum gates...
Decoherence-induced geometric phase in a multilevel atomic system (2006)
Dasgupta, Shubhrangshu, Lidar, Daniel A.
We consider the STIRAP process in a three-level atom. Viewed as a closed system, no geometric phase is acquired. But in the presence of spontaneous emission and/or collisional relaxation we show...
Optimal Control of High-Fidelity Quantum Gates in the Presence of Decoherence (2006)
Grace, Matthew, Brif, Constantin, Rabitz, Herschel, Walmsley, Ian, Kosut, Robert, Lidar, Daniel A.
This work studies the feasibility of optimal control of high-fidelity quantum gates in a model of interacting two-level particles. One set of particles serves as the quantum information processor,...
Simple proof of equivalence between adiabatic quantum computation and the circuit model (2006)
Mizel, Ari, Lidar, Daniel A., Mitchell, Morgan
We prove the equivalence between adiabatic quantum computation and quantum computation in the circuit model. An explicit adiabatic computation procedure is given that generates a ground state from...
Adiabatic Preparation of Topological Order (2006)
Hamma, Alioscia, Lidar, Daniel A.
Topological order characterizes those phases of matter that defy a description in terms of symmetry and cannot be distinguished in terms local order parameters. This type of order plays a key role in...
Khodjasteh, Kaveh, Lidar, Daniel A.
Dynamical decoupling can be used to preserve arbitrary quantum states despite undesired interactions with the environment, using control Hamiltonians affecting the system only. We present a...
Quantum Error Correction via Convex Optimization (2006)
Kosut, Robert L., Lidar, Daniel A.
We show that the problem of designing a quantum information error correcting procedure can be cast as a bi-convex optimization problem, iterating between encoding and recovery, each being a...
Robust transmission of non-Gaussian entanglement over optical fibers (2006)
Biswas, Asoka, Lidar, Daniel A.
We show how the entanglement in a wide range of continuous variable non-Gaussian states can be preserved against decoherence for long-range quantum communication through an optical fiber. We apply...
When quantum communication networks proliferate they will likely be subject to a new type of attack: by hackers, virus makers, and other malicious intruders. Here we introduce the concept of "quantum...
Few-body spin couplings and their implications for universal quantum computation (2005)
Woodworth, Ryan, Mizel, Ari, Lidar, Daniel A.
Electron spins in semiconductor quantum dots are promising candidates for the experimental realization of solid-state qubits. We analyze the dynamics of a system of three qubits arranged in a linear...
Stabilizing qubit coherence via tracking-control (2004)
Lidar, Daniel A., Schneider, Sara
We consider the problem of stabilizing the coherence of a single qubit subject to Markovian decoherence, via the application of a control Hamiltonian, without any additional resources. In this case...
Universal Leakage Elimination (2004)
Byrd, Mark S., Lidar, Daniel A., Wu, Lian-Ao, Zanardi, Paolo
``Leakage'' errors are particularly serious errors which couple states within a code subspace to states outside of that subspace thus destroying the error protection benefit afforded by an encoded...
Robustness of multi-qubit entanglement in the independent decoherence model (2004)
Bandyopadhyay, Somshubhro, Lidar, Daniel A.
We study the robustness of the GHZ (or ``cat'') class of multi-partite states under decoherence. The noise model is described by a general completely positive map for qubits independently coupled to...
Quantum Phase Transitions and Bipartite Entanglement (2004)
Wu, Lian-Ao, Sarandy, Marcelo S., Lidar, Daniel A.
We develop a general theory of the relation between quantum phase transitions (QPTs) characterized by nonanalyticities in the energy and bipartite entanglement. We derive a functional relation...
Completely Positive Post-Markovian Master Equation via a Measurement Approach (2004)
Shabani, Alireza, Lidar, Daniel A.
A new post-Markovian quantum master equation is derived, that includes bath memory effects via a phenomenologically introduced memory kernel k(t). The derivation uses as a formal tool a probabilistic...
Long-range entanglement generation via frequent measurements (2004)
Wu, Lian-Ao, Lidar, Daniel A., Schneider, Sara
A method is introduced whereby two non-interacting quantum subsystems, that each interact with a third subsystem, are entangled via repeated projective measurements of the state of the third...
Overview of Quantum Error Prevention and Leakage Elimination (2004)
Byrd, Mark S., Wu, Lian-Ao, Lidar, Daniel A.
Quantum error prevention strategies will be required to produce a scalable quantum computing device and are of central importance in this regard. Progress in this area has been quite rapid in the...
Three and Four-Body Interactions in Spin-Based Quantum Computers (2004)
In the effort to design and to construct a quantum computer, several leading proposals make use of spin-based qubits. These designs generally assume that spins undergo pairwise interactions. We point...
Exponentially Localized Magnetic Fields for Single-Spin Quantum Logic Gates (2003)
Lidar, Daniel A., Thywissen, Joseph H.
An infinite array of parallel current-carrying wires is known, from the field of neutral particle optics, to produce an exponentially localized magnetic field when the current direction is...
One-spin quantum logic gates from exchange interactions and a global magnetic field (2003)
Wu, Lian-Ao, Lidar, Daniel A., Friesen, Mark
It has been widely assumed that one-qubit gates in spin-based quantum computers suffer from severe technical difficulties. We show that one-qubit gates can in fact be generated using only modest and...
It is shown that the canonical problem of classical statistical thermodynamics, the computation of the partition function, is in the case of +/-J Ising spin glasses a particular instance of certain...
Comment on "Conservative Quantum Computing" (2003)
A Comment on the paper "Conservative Quantum Computing" by M. Ozawa, Phys. Rev. Lett. 89, 057902 (2002). The author replies in Phys. Rev. Lett. 91, 089802 (2003).
A Comment on the paper "Quantum waveguide array generator for performing Fourier transforms: Alternate route to quantum computing" by R. Akis and D.K. Ferry, Appl. Phys. Lett. 79, 2823 (2001). The...
Entangling capacities of noisy two-qubit Hamiltonians (2003)
Bandyopadhyay, Somshubhro, Lidar, Daniel A.
We show that intrinsic fluctuations in system control parameters impose limits on the ability of two-qubit (exchange) Hamiltonians to generate entanglement starting from mixed initial states. We find...
Overcoming Quantum Noise in Optical Fibers (2003)
Noise in optical Telecom fibers is an important limitation on optical quantum data transmission. Unfortunately, the classically successful amplifiers (such as EDFA) cannot be used in quantum...
Quantum Computers and Decoherence: Exorcising the Demon from the Machine (2003)
Decoherence is the main obstacle to the realization of quantum computers. Until recently it was thought that quantum error correcting codes are the only complete solution to the decoherence problem....
A Magnetic Resonance Realization of Decoherence-Free Quantum Computation (2003)
Ollerenshaw, Jason E., Lidar, Daniel A., Kay, Lewis E.
We report the realization, using nuclear magnetic resonance techniques, of the first quantum computer that reliably executes an algorithm in the presence of strong decoherence. The computer is based...
Several prominent proposals have suggested that spins of localized electrons could serve as quantum computer qubits. The exchange interaction has been invoked as a means of implementing two qubit...
Decoherence-Free Subspaces and Subsystems (2003)
Lidar, Daniel A., Whaley, K. Birgitta
Decoherence is the phenomenon of non-unitary dynamics that arises as a consequence of coupling between a system and its environment. It has important harmful implications for quantum information...
Combined Error Correction Techniques for Quantum Computing Architectures (2002)
Byrd, Mark S., Lidar, Daniel A.
Proposals for quantum computing devices are many and varied. They each have unique noise processes that make none of them fully reliable at this time. There are several error correction/avoidance...
Khodjasteh, Kaveh L., Lidar, Daniel A.
A universal and fault tolerant scheme for quantum computation is proposed which utilizes a class of error correcting codes that is based on the detection of spontaneous emission (of, e.g., photons,...
Empirical Determination of Bang-Bang Operations (2002)
Byrd, Mark S., Lidar, Daniel A.
Strong and fast "bang-bang" (BB) pulses have been recently proposed as a means for reducing decoherence in a quantum system. So far theoretical analysis of the BB technique relied on model...
Lidar, Daniel A., Wu, Lian-Ao, Blais, Alexandre
We introduce simple qubit-encodings and logic gates which eliminate the need for certain difficult single-qubit operations in superconducting phase-qubits, while preserving universality. The simplest...
Byrd, Mark S., Lidar, Daniel A.
Proposals for scalable quantum computing devices suffer not only from decoherence due to the interaction with their environment, but also from severe engineering constraints. Here we introduce a...
Bang-Bang Operations from a Geometric Perspective (2001)
Byrd, Mark S., Lidar, Daniel A.
Strong, fast pulses, called ``bang-bang'' controls can be used to eliminate the effects of system-environment interactions. This method for preventing errors in quantum information processors is...
Bihary, Zsolt, Glenn, David R., Lidar, Daniel A., Apkarian, V. Ara
Time-Frequency Resolved Coherent Anti-Stokes Raman Scattering (TFRCARS) was recently proposed as a means to implement quantum logic using the molecular ro-vibrational manifold as a quantum register...
From Completely Positive Maps to the Quantum Markovian Semigroup Master Equation (2000)
Lidar, Daniel A., Bihary, Zsolt, Whaley, K. Birgitta
A central problem in the theory of the dynamics of open quantum systems is the derivation of a rigorous and computationally tractable master equation for the reduced system density matrix. Most...
Analysis of Generalized Grover's Quantum Search Algorithms Using Recursion Equations (2000)
Biham, Eli, Biham, Ofer, Biron, David, Grassl, Markus, Lidar, Daniel A., Shapira, Daniel
The recursion equation analysis of Grover's quantum search algorithm presented by Biham et al. [PRA 60, 2742 (1999)] is generalized. It is applied to the large class of Grover's type algorithms in...
Lidar, Daniel A., Bacon, Dave, Kempe, Julia, Whaley, K. B.
Decoherence-free subspaces (DFSs) shield quantum information from errors induced by the interaction with an uncontrollable environment. Here we study a model of correlated errors forming an Abelian...
Theory of Decoherence-Free Fault-Tolerant Universal Quantum Computation (2000)
Kempe, Julia, Bacon, Dave, Lidar, Daniel A., Whaley, K. Birgitta
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...
Universal Fault-Tolerant Computation on Decoherence-Free Subspaces (1999)
Bacon, Dave, Kempe, Julia, Lidar, Daniel A., Whaley, K. B.
A general scheme to perform universal quantum computation within decoherence-free subspaces (DFSs) of a system's Hilbert space is presented. This scheme leads to the first fault-tolerant realization...
Decoherence-Free Subspaces for Multiple-Qubit Errors: (I) Characterization (1999)
Lidar, Daniel A., Bacon, Dave, Kempe, Julia, Whaley, K. B.
Coherence in an open quantum system is degraded through its interaction with a bath. This decoherence can be avoided by restricting the dynamics of the system to special decoherence-free subspaces....
Pattern Formation and a Clustering Transition in Power-Law Sequential Adsorption (1999)
Biham, Ofer, Malcai, Ofer, Lidar, Daniel A., Avnir, David
A new model that describes adsorption and clustering of particles on a surface is introduced. A {\it clustering} transition is found which separates between a phase of weakly correlated particle...
Protecting Quantum Information Encoded in Decoherence Free States Against Exchange Errors (1999)
Lidar, Daniel A., Bacon, David, Kempe, Julia, Whaley, K. Birgitta
The exchange interaction between identical qubits in a quantum information processor gives rise to unitary two-qubit errors. It is shown here that decoherence free subspaces (DFSs) for collective...
Inversion of Randomly Corrugated Surfaces Structure from Atom Scattering Data (1999)
The Sudden Approximation is applied to invert structural data on randomly corrugated surfaces from inert atom scattering intensities. Several expressions relating experimental observables to surface...
Grover's Quantum Search Algorithm for an Arbitrary Initial Amplitude Distribution (1998)
Biham, Eli, Biham, Ofer, Biron, David, Grassl, Markus, Lidar, Daniel A.
Grover's algorithm for quantum searching is generalized to deal with arbitrary initial complex amplitude distributions. First order linear difference equations are found for the time evolution of the...
How to Teleport Superpositions of Chiral Amplitudes (1998)
Maierle, Christopher S., Lidar, Daniel A., Harris, Robert A.
Chiral molecules may exist in superpositions of left- and right-handed states. We show how the amplitudes of such superpositions may be teleported to the polarization degrees of freedom of a photon...
Calculating the Thermal Rate Constant with Exponential Speed-Up on a Quantum Computer (1998)
Lidar, Daniel A., Wang, Haobin
It is shown how to formulate the ubiquitous quantum chemistry problem of calculating the thermal rate constant on a quantum computer. The resulting exact algorithm scales exponentially faster with...
The Sudden Approximation (SA) for scattering of atoms from surfaces is generalized to allow for double collision events and scattering from time-dependent quantum liquid surfaces. The resulting new...
Generalized Grover Search Algorithm for Arbitrary Initial Amplitude Distribution (1998)
Biron, David, Biham, Ofer, Biham, Eli, Grassl, Markus, Lidar, Daniel A.
Grover's algorithm for quantum searching of a database is generalized to deal with arbitrary initial amplitude distributions. First order linear difference equations are found for the time evolution...
Scaling Range and Cutoffs in Empirical Fractals (1998)
Malcai, Ofer, Lidar, Daniel A., Biham, Ofer, Avnir, David
Fractal structures appear in a vast range of physical systems. A literature survey including all experimental papers on fractals which appeared in the six Physical Review journals (A-E and Letters)...
The Limited Scaling Range of Empirical Fractals (1998)
Avnir, David, Biham, Ofer, Lidar, Daniel A., Malcai, Ofer
The notion of the abundance of fractals is critically re-examined in light of surprising data regarding the scaling range in empirical reports on fractality.
Limited Range Fractality of Randomly Adsorbed Rods (1997)
Lidar, Daniel A., Biham, Ofer, Avnir, David
Multiple resolution analysis of two dimensional structures composed of randomly adsorbed penetrable rods, for densities below the percolation threshold, has been carried out using box-counting...
Simulating Ising Spin Glasses on a Quantum Computer (1996)
A linear-time algorithm is presented for the construction of the Gibbs distribution of configurations in the Ising model, on a quantum computer. The algorithm is designed so that each run provides...