Limits...
Conditional cooling limit for a quantum channel going through an incoherent environment.

Straka I, Miková M, Mičuda M, Dušek M, Ježek M, Filip R - Sci Rep (2015)

Bottom Line: We propose and experimentally verify a cooling limit for a quantum channel going through an incoherent environment.The environment consists of a large number of independent non-interacting and non-interfering elementary quantum systems--qubits.The limit specifies when the single-qubit channel is quantum, i.e. it preserves entanglement.

View Article: PubMed Central - PubMed

Affiliation: Department of Optics, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic.

ABSTRACT
We propose and experimentally verify a cooling limit for a quantum channel going through an incoherent environment. The environment consists of a large number of independent non-interacting and non-interfering elementary quantum systems--qubits. The qubits travelling through the channel can only be randomly replaced by environmental qubits. We investigate a conditional cooling limit that exploits an additional probing output. The limit specifies when the single-qubit channel is quantum, i.e. it preserves entanglement. It is a fundamental condition for entanglement-based quantum technology.

No MeSH data available.


Related in: MedlinePlus

The schematics of the incoherent channel.Since we assume one qubit in each output, we will distinguish the qubits and outputs commonly by R, A, B. A qubit entangled with qubit R is propagated through an incoherent environment. The environment consists of many qubits in a mixture of the states , . A projective measurement is carried out on output B, conditioning an entanglement preservation on output A.
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f1: The schematics of the incoherent channel.Since we assume one qubit in each output, we will distinguish the qubits and outputs commonly by R, A, B. A qubit entangled with qubit R is propagated through an incoherent environment. The environment consists of many qubits in a mixture of the states , . A projective measurement is carried out on output B, conditioning an entanglement preservation on output A.

Mentions: In this paper, we derive and experimentally verify a conditional cooling limit for quantum channel with incoherent environment with many independent noisy qubits. To derive the conditional limit, we extract an auxiliary qubit B from the incoherent environment, as is depicted in Fig. 1. It can be advantageously used to herald more entanglement between qubits R and A, thus beating the unconditional cooling limit. In this approach, the entanglement is fully broken only if the qubit entering the environment is lost and two completely incoherent environmental qubits appear at the outputs of the environment. The probability of the qubit being lost is PL. We derive a limit on a joint error represented by the product pTPL, depending on temperature T for thermal environment. The limit is given by the probability PS of successful implementation of the ideal quantum channel. We experimentally verify this fundamental cooling limit using a quantum optics experiment with a simulated, controllable environment. However, it must be noted that our analysis is not limited solely to thermal environments or single photons; it is applicable to any environment consisting of independent non-interacting and non-interfering qubits. The conditional cooling limit for qubit quantum channel is universal, widely applicable for different physical platforms.


Conditional cooling limit for a quantum channel going through an incoherent environment.

Straka I, Miková M, Mičuda M, Dušek M, Ježek M, Filip R - Sci Rep (2015)

The schematics of the incoherent channel.Since we assume one qubit in each output, we will distinguish the qubits and outputs commonly by R, A, B. A qubit entangled with qubit R is propagated through an incoherent environment. The environment consists of many qubits in a mixture of the states , . A projective measurement is carried out on output B, conditioning an entanglement preservation on output A.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644953&req=5

f1: The schematics of the incoherent channel.Since we assume one qubit in each output, we will distinguish the qubits and outputs commonly by R, A, B. A qubit entangled with qubit R is propagated through an incoherent environment. The environment consists of many qubits in a mixture of the states , . A projective measurement is carried out on output B, conditioning an entanglement preservation on output A.
Mentions: In this paper, we derive and experimentally verify a conditional cooling limit for quantum channel with incoherent environment with many independent noisy qubits. To derive the conditional limit, we extract an auxiliary qubit B from the incoherent environment, as is depicted in Fig. 1. It can be advantageously used to herald more entanglement between qubits R and A, thus beating the unconditional cooling limit. In this approach, the entanglement is fully broken only if the qubit entering the environment is lost and two completely incoherent environmental qubits appear at the outputs of the environment. The probability of the qubit being lost is PL. We derive a limit on a joint error represented by the product pTPL, depending on temperature T for thermal environment. The limit is given by the probability PS of successful implementation of the ideal quantum channel. We experimentally verify this fundamental cooling limit using a quantum optics experiment with a simulated, controllable environment. However, it must be noted that our analysis is not limited solely to thermal environments or single photons; it is applicable to any environment consisting of independent non-interacting and non-interfering qubits. The conditional cooling limit for qubit quantum channel is universal, widely applicable for different physical platforms.

Bottom Line: We propose and experimentally verify a cooling limit for a quantum channel going through an incoherent environment.The environment consists of a large number of independent non-interacting and non-interfering elementary quantum systems--qubits.The limit specifies when the single-qubit channel is quantum, i.e. it preserves entanglement.

View Article: PubMed Central - PubMed

Affiliation: Department of Optics, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic.

ABSTRACT
We propose and experimentally verify a cooling limit for a quantum channel going through an incoherent environment. The environment consists of a large number of independent non-interacting and non-interfering elementary quantum systems--qubits. The qubits travelling through the channel can only be randomly replaced by environmental qubits. We investigate a conditional cooling limit that exploits an additional probing output. The limit specifies when the single-qubit channel is quantum, i.e. it preserves entanglement. It is a fundamental condition for entanglement-based quantum technology.

No MeSH data available.


Related in: MedlinePlus