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We consider a two reservoir model of quantum error correction with a hot bath causing errors in the qubits and a cold bath cooling the ancilla qubits to a fiducial state. We consider error correction protocols both with and without…

Quantum Physics · Physics 2009-11-11 James P. Clemens , Julio Gea-Banacloche

We describe a quantum computer based upon the coherent manipulation of two-level atoms between discrete one-dimensional momentum states. Combinations of short laser pulses with kinetic energy dependent free phase evolution can perform the…

Quantum Physics · Physics 2009-11-07 Tim Freegarde , Danny Segal

Current and near term quantum computers (i.e. NISQ devices) are limited in their computational power in part due to qubit decoherence. Here we seek to take advantage of qubit decoherence as a resource in simulating the behavior of real…

Quantum computation requires many qubits that can be coherently controlled and coupled to each other. Qubits that are defined using lithographic techniques are often argued to be promising platforms for scalability, since they can be…

Mesoscale and Nanoscale Physics · Physics 2020-04-27 L. Petit , H. G. J. Eenink , M. Russ , W. I. L. Lawrie , N. W. Hendrickx , J. S. Clarke , L. M. K. Vandersypen , M. Veldhorst

The cooling effects of a quantum LC circuit coupled inductively with an ensemble of artificial qubits are investigated. The particles may decay independently or collectively through their interaction with the environmental vacuum…

Quantum Physics · Physics 2015-05-18 Mihai A. Macovei

Heat-bath algorithmic cooling (HBAC) provides algorithmic ways to improve the purity of quantum states. These techniques are complex iterative processes that change from each iteration to the next and this poses a significant challenge to…

Quantum Physics · Physics 2019-06-12 Sadegh Raeisi , Mária Kieferová , Michele Mosca

An electron inside liquid helium forms a bubble of 17 \AA in radius. In an external magnetic field, the two-level system of a spin 1/2 electron is ideal for the implementation of a qubit for quantum computing. The electron spin is well…

Other Condensed Matter · Physics 2007-05-23 Weijun Yao

Spin qubits in gate-defined quantum dots (QDs) are emerging as a leading technology due to their scalability and long coherence times. However, maintaining these qubits at ultra-low temperatures typically requires complex cryogenic systems.…

Mesoscale and Nanoscale Physics · Physics 2024-10-29 Daryoosh Vashaee , Jahanfar Abouie

We study theoretically the cooling of an ensemble of nuclear spins coupled to the spin of a localized electron in a quantum dot. We obtain a master equation for the state of the nuclear spins interacting with a sequence of polarized…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 H. Christ , J. I. Cirac , G. Giedke

We address the problem of cooling a Markovian quantum system to a pure state in the shortest amount of time possible. Here the system drift takes the form of a Lindblad master equation and we assume fast unitary control. This setting allows…

Quantum Physics · Physics 2024-03-11 Emanuel Malvetti

Many protocols in quantum science and technology require initializing a system in a pure quantum state. In the context of the motional state of massive resonators, this enables studying fundamental physics at the elusive quantum-classical…

Quantum Physics · Physics 2023-03-07 Sampo A. Saarinen , Nenad Kralj , Eric C. Langman , Yeghishe Tsaturyan , Albert Schliesser

Quantum computers are expected to outperform conventional computers for a range of important problems, from molecular simulation to search algorithms, once they can be scaled up to large numbers of quantum bits (qubits), typically millions.…

We investigate, theoretically and experimentally, the thermodynamic performance of a minimal three-qubit heat-bath algorithmic cooling refrigerator. We analytically compute the coefficient of performance, the cooling power and the…

Quantum Physics · Physics 2022-07-12 Rodolfo Soldati , Durga Bhaktavatsala Rao Dasari , Jörg Wrachtrup , Eric Lutz

Algorithmic cooling shows that it is possible to locally reduce the entropy of a qubit belonging to an isolated ensemble such as nuclear spins in molecules or nitrogen-vacancy centers in diamonds. In the same physical setting, we introduce…

We introduce a scheme for deep laser cooling of molecules based on robust dark states at zero velocity. By simulating this scheme, we show it to be a widely applicable method that can reach the recoil limit or below. We demonstrate and…

Atomic Physics · Physics 2019-07-24 L. Caldwell , J. A. Devlin , H. J. Williams , N. J. Fitch , E. A. Hinds , B. E. Sauer , M. R. Tarbutt

Using a Bang-Bang optimal control (BB) technique, we transfer polarization from abundant high-$\gamma$ nuclei directly to singlet order. This approach is analogous to algorithmic cooling (AC) procedure used in quantum state purification.…

Quantum Physics · Physics 2018-05-29 Deepak Khurana , T. S. Mahesh

The coherence of quantum systems is crucial to quantum information processing. While it has been demonstrated that superconducting qubits can process quantum information at microelectronics rates, it remains a challenge to preserve the…

Nature is governed by precise physical laws, which can inspire the discovery of new computer-run simulation algorithms. Thermal states are the most ubiquitous for they are the equilibrium states of matter. Simulating thermal states of…

Quantum Physics · Physics 2023-04-13 Oles Shtanko , Ramis Movassagh

Quantum Information processing by NMR with small number of qubits is well established. Scaling to higher number of qubits is hindered by two major requirements (i) mutual coupling among qubits and (ii) qubit addressability. It has been…

Quantum Physics · Physics 2009-11-10 Ranabir Das , Rangeet Bhattacharyya , Anil Kumar

Scalable, coherent many-body systems can enable the realization of previously unexplored quantum phases and have the potential to exponentially speed up information processing. Thermal fluctuations are negligible and quantum effects govern…